Problem:
Score : 300 points

Problem Statement

We have a square grid with H rows and W columns.
Snuke wants to write 0 or 1 in each of the squares.
Here, all of the following conditions have to be satisfied:

For every row, the smaller of the following is A: the number of 0s contained in the row, and the number of 1s contained in the row. (If these two numbers are equal, “the smaller” should be read as “either”.)

For every column, the smaller of the following is B: the number of 0s contained in the column, and the number of 1s contained in the column.

Determine if these conditions can be satisfied by writing 0 or 1 in each of the squares. If the answer is yes, show one way to fill the squares so that the conditions are satisfied.

Constraints

1 \leq H,W \leq 1000

0 \leq A

2 \times A \leq W

0 \leq B

2 \times B \leq H

All values in input are integers.

Input

Input is given from Standard Input in the following format:

H W A B

Output

If the conditions cannot be satisfied by writing 0 or 1 in each of the squares, print -1.

If the conditions can be satisfied, print one way to fill the squares so that the conditions are satisfied, in the following format:

s_{11}s_{12}\cdots s_{1W}
s_{21}s_{22}\cdots s_{2W}
\vdots
s_{H1}s_{H2}\cdots s_{HW}

Here s_{ij} is the digit written in the square at the i-th row from the top and the j-th column from the left in the grid.

If multiple solutions exist, printing any of them will be accepted.

Sample Input 1

3 3 1 1

Sample Output 1

100
010
001

Every row contains two 0s and one 1, so the first condition is satisfied.
Also, every column contains two 0s and one 1, so the second condition is satisfied.

Sample Input 2

1 5 2 0

Sample Output 2

01010

Solution in Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.io.*;
import java.util.*;

class Main{
    final static long INF = Long.MAX_VALUE / 2;
    final static int MOD = 1_000_000_007;
    final static int SIZE = 1_000_000;
    long[] fac = new long[SIZE];
    long[] inv = new long[SIZE];
    long[] finv = new long[SIZE];
    FastScanner sc = new FastScanner();

    public static void main(String[] args) {
        new Main().solve();
    }

    void solve(){

        int h = sc.nextInt();
        int w = sc.nextInt();
        int a = sc.nextInt();
        int b = sc.nextInt();
        int[][] m = new int[h][w];

        for(int i = b; i < h; i++){
            for(int j = 0; j < a; j++){
                m[i][j] = 1;
            }
        }

        for(int i = 0; i < b; i++){
            for(int j = a; j < w; j++){
                m[i][j] = 1;
            }
        }

        for(int i = 0; i < h; i++){
            for(int j = 0; j < w; j++){
                System.out.print(m[i][j]);
            }
            System.out.println();
        }

    }

    long gcd(long a, long b){ // return aとbの最大公約数
        if(b == 0){
          return a;
        }
        return gcd(b, a % b);
    }

    long lcm(long a, long b){ // return aとbの最小公倍数
        return a * b / gcd(a, b);
    }

    long inv(long a){ // return aの逆元 (mod MOD)
        return pow(a, MOD - 2);
    }

    long pow(long a, long r){ // return a^r (mod MOD)
        long sum = 1;
        while(r > 0){
            if((r & 1) == 1){ // 2進数表記で末尾1の時
                sum *= a;
                sum %= MOD;
            }
            a *= a;
            a %= MOD;
            r >>= 1;
        }
        return sum;
    }

    long modFact(long n){ // retur n! (mod MOD)
        if(n == 0){
            return 1;
        }
        return n * modFact(n - 1) % MOD;
    }

    long fact(long n){ // return n!
        if(n == 0){
            return 1;
        }
        return n * fact(n - 1);
    }

    void initCOMB(){
        fac[0] = fac[1] = 1;
        inv[1] = 1;
        finv[0] = finv[1] = 1;
        for(int i = 2; i < SIZE; i++){
            fac[i] = fac[i - 1] * i % MOD;
            inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
            finv[i] = finv[i - 1] * inv[i] % MOD;
        }
    }

    long modComb(int n, int r){ // return nCr (先にinitCOMB()必要)
        if(n < r || n < 0 || r < 0) return 0;
        return fac[n] * finv[r] % MOD * finv[n - r] % MOD;
    }

    long comb(long n, long r){ // return nCr
        long num = 1;
        for(long i = 1; i <= r; i++){
            num = num * (n - i + 1) / i;
        }
        return num;
    }

    boolean isPrime(long a){ // aの素数判定
        if(a <= 1) return false;
        for(int i = 2; i * i <= a; i++){
            if(a % i == 0) return false;
        }
        return true;
    }

    int lowerBound(long[] a, long v){ // return 配列a内のv以上の要素の内最低の要素のイテレータ
        int r = a.length;
        int l = -1;
        while(r - l > 1){
            int mid = (r + l) / 2;
            if(a[mid] >= v){
                r = mid;
            }else{
                l = mid;
            }
        }
        return r;
    }

    int upperBound(long[] a, long v){ // return 配列a内のvより大きい要素の内最低の要素のイテレータ
        int r = a.length;
        int l = -1;
        while(r - l > 1){
            int mid = (r + l) / 2;
            if(a[mid] > v){
                r = mid;
            }else{
                l = mid;
            }
        }
        return r;
    }

    String nextPermutation(String s){ // return sの次の順列
        ArrayList<Character> list = new ArrayList<>();
        for(int i = 0; i < s.length(); i++) list.add(s.charAt(i));

        int pivotPos = -1;
        char pivot = 0;
        for(int i = list.size() - 2; i >= 0; i--){
            if(list.get(i) < list.get(i+1)){
    			pivotPos = i;
    			pivot = list.get(i);
    			break;
    		}
    	}

        if(pivotPos == -1 && pivot == 0) return null;

        int L = pivotPos + 1;
        int R = list.size() - 1;
    	int minPos = -1;
    	char min = Character.MAX_VALUE;
    	for(int i = R; i >= L; i--){
    		if(pivot < list.get(i)){
    			if(list.get(i) < min){
    				min = list.get(i);
    				minPos = i;
    			}
    		}
    	}

    	Collections.swap(list, pivotPos, minPos);
    	Collections.sort(list.subList(L, R + 1));

    	StringBuilder sb = new StringBuilder();
    	for(int i=0; i<list.size(); i++) sb.append(list.get(i));

    	return sb.toString();
    }

    boolean nextPermutation(long[] a){
        for(int i = a.length - 1; i > 0; i--){
            if(a[i - 1] < a[i]){
                int swapIndex = find(a[i - 1], a, i, a.length - 1);
                long temp = a[swapIndex];
                a[swapIndex] = a[i - 1];
                a[i - 1] = temp;
                Arrays.sort(a, i, a.length);
                return true;
            }
        }
        return false;
    }

    int find(long dest, long[] a, int s, int e){
        if(s == e){
            return s;
        }
        int m = (s + e + 1) / 2;
        return a[m] <= dest ? find(dest, a, s, m - 1) : find(dest, a, m, e);
    }

    void elimination(int[][] a, int[] b) {
        int n = a.length;
        double f;
        for(int k = 0; k < n - 1; k++){
            for(int i = k + 1; i < n; i++){
                f = - a[i][k] / a[k][k];
                for(int j = k + 1; j < n; j++){
                    a[i][j] += f * a[k][j];
                }
                b[i] += f * b[k];
            }
            for(int i = n - 1; i >= 0; i--){
                for(int j = i + 1; j < n; j++){
                    b[i] -= a[i][j] * b[j];
                }
                b[i] = b[i] / a[i][i];
            }
        }
    }



    class SegmentTree{

        //------------------------------------------------------------
        // 2 * n - 1 : 木全体のノード数
        // i + n - 1 : 配列のi番目が対応するノードの番号
        // 2 * i + 1, 2 * i + 2 : i番目のノードの子ノードの番号
        // (i - 1) / 2 : i番目のノードの親ノードの番号
        //
        // int n = sc.nextInt();
        // long[] a = new long[n];
        // for(int i = 0; i < n; i++) a[i] = sc.nextLong();
        // SegmentTree st = new SegmentTree(a);
        // int l = sc.nextInt() - 1;
        // int r = sc.nextInt() - 1;
        // System.out.println(st.query(l, r));
        //------------------------------------------------------------

        final static long INF = Long.MAX_VALUE / 2;

        // long e = INF; // 単位元
        long e = 0;
        long func(long a, long b){ // 処理
            // return Math.min(a, b);
            return a + b;
        }

        int n; // 配列の要素数を超える最小の2のべき乗
        long[] node;

        SegmentTree(long[] a){
            init(a);
        }

        void init(long[] a){ // 配列aで初期化
            n = 1;
            while(n < a.length){
                n *= 2;
            }
            node = new long[2 * n - 1];
            Arrays.fill(node, e);
            for(int i = 0; i < a.length; i++){
                node[i + n - 1] = a[i];
            }
            for(int i = n - 2; i >= 0; i--){
                node[i] = func(node[2 * i + 1], node[2 * i + 2]);
            }
        }

        void update(int p, long v){ // 配列のp番目をvに変更し、木全体を更新
            p = p + n - 1;
            node[p] = v;
            while(p > 0){
                p = (p - 1) / 2;
                node[p] = func(node[2 * p + 1], node[2 * p + 2]);
            }
        }

        long query(int a, int b){ // 区間[a, b)についてクエリを処理
            return query(a, b, 0, 0, n);
        }

        long query(int a, int b, int k, int l, int r){
            if(r <= a || b <= l) return e;
            if(a <= l && r <= b) return node[k];
            return func(query(a, b, 2 * k + 1, l, (l + r) / 2), query(a, b, 2 * k + 2, (l + r) / 2, r));
        }

    }



    class UnionFindTree{

        //------------------------------------------------------------
        // int n = sc.nextInt();
        // int q = sc.nextInt();
        // UnionFindTree uft = new UnionFindTree(n);
        // List<String> ans = new ArrayList<>();
        // for(int i = 0; i < q; i++){
        //     int p = sc.nextInt(); // 0 : union, 1 : same
        //     if(p == 0){
        //         int a = sc.nextInt() - 1;
        //         int b = sc.nextInt() - 1;
        //         uft.union(a, b);
        //     }else if(p == 1){
        //         int a = sc.nextInt() - 1;
        //         int b = sc.nextInt() - 1;
        //         if(uft.same(a, b)) ans.add("Yes");
        //         else ans.add("No");
        //     }
        // }
        // for(String s : ans){
        //     System.out.println(s);
        // }
        //------------------------------------------------------------

        int[] parent; // インデックスにとノードを対応させ、そのルートノードのインデックスを格納
        int[] rank; // parentと同様に、木の高さを格納

        UnionFindTree(int size){
            parent = new int[size];
            rank = new int[size];

            for(int i = 0; i < size; i++){
                makeSet(i);
            }
        }

        void makeSet(int i){
            parent[i] = i;
            rank[i] = 0;
        }

        void union(int x, int y){
            int xRoot = find(x);
            int yRoot = find(y);

            if(rank[xRoot] > rank[yRoot]){ // xが属する木の方が大きい場合
                parent[yRoot] = xRoot;
            }else if(rank[xRoot] < rank[yRoot]){
                parent[xRoot] = yRoot; // yの親をxに更新
            }else{
                parent[yRoot] = xRoot;
                rank[xRoot]++; // 同じ高さの木がルートの子として着くから大きさ++;
            }
        }

        int find(int i){ // iの属するルートを返す
            if(i != parent[i]){
                parent[i] = find(parent[i]);
            }
            return parent[i];
        }

        boolean same(int x, int y){ // xとyが同じ木に属しているかを返す
            return find(x) == find(y);
        }

    }



}



class Pair implements Comparable<Pair>{
    long a, b;
    public Pair(long i, long j){
        a = i;
        b = j;
    }

    @Override
    public int compareTo(Pair p){
        if(this.b < p.b) return -1;
        else if(this.b > p.b) return 1;
        else return 0;
    }

    @Override
    public String toString(){
        return a + " " + b;
    }
}



class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private boolean hasNextByte(){
        if(ptr < buflen){
            return true;
        }else{
            ptr = 0;
            try{
                buflen = in.read(buffer);
            }catch(IOException e){
                e.printStackTrace();
            }
            if(buflen <= 0){
                return false;
            }
        }
        return true;
    }
    private int readByte(){
        if(hasNextByte()) return buffer[ptr++];
        else return -1;
    }
    private static boolean isPrintableChar(int c){
        return 33 <= c && c <= 126;
    }
    public boolean hasNext(){
        while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
        return hasNextByte();
    }
    public String next(){
        if(!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)){
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }
    public long nextLong(){
        if(!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if(b == '-'){
            minus = true;
            b = readByte();
        }
        if(b < '0' || '9' < b){
            throw new NumberFormatException();
        }
        while(true){
            if('0' <= b && b <= '9'){
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
    public int nextInt(){
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }
    public double nextDouble(){
        return Double.parseDouble(next());
    }
}