Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func lcs(a, b string) int {
	lenA := len(a)
	lenB := len(b)
	dp := make([][]int, lenA+1)
	for i := range dp {
		dp[i] = make([]int, lenB+1)
	}

	for i := 1; i <= lenA; i++ {
		for j := 1; j <= lenB; j++ {
			if a[i-1] == b[j-1] {
				dp[i][j] = dp[i-1][j-1] + 1
			} else {
				dp[i][j] = max(dp[i][j-1], dp[i-1][j])
			}
		}
	}
	return dp[lenA][lenB]
}

func main() {
	n := scanInt()
	w := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		a := scanString()
		b := scanString()
		fmt.Fprintln(w, lcs(a, b))
	}
	w.Flush()
}

C++: #include<iostream>
#include<string>
using namespace std;

const int MAX_N=1e3+5;

string s1,s2;

int dp[MAX_N][MAX_N];


int lcs(int i,int j){
	if(i==s1.size() || j==s2.size())return 0;
	if(dp[i][j]!=-1)return dp[i][j];
	if(s1[i]==s2[j])return dp[i][j]=lcs(i+1,j+1)+1;
	return dp[i][j]=max(lcs(i+1,j),lcs(i,j+1));
}

int main(){
	int n;
	cin>>n;
	for(int i=0;i<n;i++){
		s1.clear();s2.clear();
		for(int j=0;j<MAX_N;j++)fill(dp[j],dp[j]+MAX_N,-1);
		cin>>s1>>s2;
		cout<<lcs(0,0)<<endl;
	}
}

C++: #include <iostream>
#include <string>
using namespace std;

int lcs(string &X, string &Y) {
  int dp[1000 + 1][1000 + 1];
  int max = 0;
  int m = X.size();
  int n = Y.size();
  X = ' ' + X;
  Y = ' ' + Y;

  for (int i = 1; i <= m; i++)
    dp[i][0] = 0;

  for (int i = 1; i <= n; i++)
    dp[0][i] = 0;

  for (int i = 1; i <= m; i++) {
    for (int j = 1; j <= n; j++) {
      if (X[i] == Y[j])
	dp[i][j] = dp[i-1][j - 1] + 1;
      else if (dp[i - 1][j] >= dp[i][j - 1])
	dp[i][j] = dp[i - 1][j];
      else
	dp[i][j] = dp[i][j - 1];

      if(max < dp[i][j])
	max = dp[i][j];
    }
  }

  return max;
}

int main() {
  int N = 0;
  cin >> N;

  string X, Y;
  for (int i = 0; i < N; i++) {
    cin >> X >> Y;

    cout << lcs(X, Y) << endl;
  }

  return 0;
}

C++: #include <iostream>
#include <string>
using namespace std;

int longestCommonSubsequence(string X, string Y) {
	int DP_memory[1000+1][1000+1]; //0~length??????

	for (unsigned int i = 0; i <= X.length(); i++)
		DP_memory[i][0] = 0;
	for (unsigned int i = 0; i <= Y.length(); i++)
		DP_memory[0][i] = 0;

	for (unsigned int i = 1; i <= X.length(); i++) {
		for (unsigned int j = 1; j <= Y.length(); j++) {
			if (X[i] == Y[j])
				DP_memory[i][j] = DP_memory[i - 1][j - 1] + 1;
			else if (DP_memory[i - 1][j] >= DP_memory[i][j - 1])
				DP_memory[i][j] = DP_memory[i - 1][j];
			else
				DP_memory[i][j] = DP_memory[i][j - 1];
		}
	}
	return DP_memory[X.length()][Y.length()];
}

int main() {
	string lcsX[1000];
	string lcsY[1000];
	int setNum;

	cin >> setNum;
	for (int i = 0; i < setNum; i++) {
		cin >> lcsX[i];
		cin >> lcsY[i];

		int lcs = longestCommonSubsequence(lcsX[i], lcsY[i]);
		cout << lcs << endl;
	}
	return 0;
}

C++: #include <iostream>

using namespace std;

int lcs(string X, string Y) {
  int memo[1010][1010];
  int m = X.size();
  int n = Y.size();
  X = ' ' + X;
  Y = ' ' + Y;
  for (int i = 0; i < m; i++) {
    memo[i][0] = 0;
  }
  for (int j = 0; j < m; j++) {
    memo[0][j] = 0;
  }
  int max_lcs = 0;
  for (int i = 1; i <= m; i++) {
    for (int j = 1; j <= n; j++) {
      if (X[i] == Y[j]) {
        memo[i][j] = memo[i-1][j-1] + 1;
      } else {
        memo[i][j] = max(memo[i][j-1], memo[i-1][j]);
      }
      max_lcs = max(max_lcs, memo[i][j]);
    }
  }
  return max_lcs;
}

int main() {
  int q;
  cin >> q;
  for (int i = 0; i < q; i++) {
    string X, Y;
    cin >> X >> Y;
    cout << lcs(X, Y) << endl;
  }
}

C++: #include<iostream>
#include<map>
#include<deque>
#include<algorithm>
#include<string>
#include<cctype>
using namespace std;
#define REP(i,b,e) for(int i=(int)b;i<(int)e;i++)
#define Rep(i,n) REP(i,0,n)
typedef long long ll;

int q;
string X,Y;
int c[1003][1003];


int main(){
    cin>>q;
    Rep(i,q){
        cin>>X>>Y;
        int m,n;
        int maxl=0;
        m=X.size();
        n=Y.size();
        Rep(j,m+1) c[j][0]=0;
        Rep(k,n+1) c[0][k]=0;
        REP(j,1,m+1){
            REP(k,1,n+1){
                if(X[j]==Y[k]) c[i][j]=c[i-1][j-1]+1;
                else c[i][j]=max(c[i-1][j],c[i][j-1]);
                maxl=max(maxl,c[i][j]);
            }
        }
        cout<<maxl<<endl;
    }
    return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
using namespace std;
 
static const int N = 1000;
 
int las(string x, string y) {
int c[N + 1][N + 1];
int m = x.size();
int n = y.size();
int maxl = 0;
x = ' ' + x;
y = ' ' + y;
for ( int i = 1; i<= m; i++ ) c[i][0] = 0;
for ( int j = 1; j <= n; j++ ) c[0][j] = 0;
 
for ( int i = 1; i <= m; i++ ) {
for ( int j = 1; j <= n; j++ ) {
if ( x[i] == y[j] ) {
c[i][j] = c[i - 1][j - 1] + 1;
} else {
c[i][j] = max(c[i - 1][j], c[i][j - 1]);
}
maxl = max(maxl, c[i][j]);
}
}
 
return mail;
}
 
int main() {
string s1, s2;
int n; cin >> n;
for ( int i = 0; i < n; i++ ) {
cin >> s1 >> s2;
cout << les(s1, s2) << endl;
}
return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
#include <cstdlib> 
using namespace std;
static const int N = 1000;

int lcs(string X,string Y){
	int **c=(int **)malloc(sizeof(int *)*1001);
	for(int i=0;i<1001;i++){
		c[i]=(int *)malloc(sizeof(int)*1001);
	}
	int m=X.size();
	int n=Y.size();
	int maxl=0;
	X=' '+X;
	Y=' '+Y;
	c[0][0]=0;
	for(int i=1;i<=m;i++) c[i][0]=0;
	for(int j=1;j<=n;j++) c[0][j]=0;
	
	for(int i=1;i<=m;i++){
		for(int j=1;j<=n;j++){
			if(X[i]==Y[j]){
				c[i][j]=c[i-1][j-1]+1;
			}else{
				c[i][j]=max(c[i-1][j],c[i][j-1]);
			}
			maxl=max(maxl,c[i][j]);
		}
	}
	return maxl;
}

int main(){
	string s1,s2;
	int n;cin>>n;
	for(int i=0;i<n;i++){
		cin >> s1 >> s2;
		cout << lcs(s1,s2) << endl;
	}
	return 0;
}

C++: #include <iostream>
#include <cstring>

using namespace std;

int main(void)
{
    int q;
    char x[1001], y[1001];
    int table[1001][1001];
    
    cin >> q;
    for (int i = 0; i < q; i++) {
        cin >> x >> y;
        int xl = strlen(x), yl = strlen(y);

        for (int i = 0; i < xl; i++)
            for (int j = 0; j < yl; j++)
                if (x[i] == y[j])
                    table[i+1][j+1] = 1 + table[i][j];
                else
                    table[i+1][j+1] = max(table[i][j+1], table[i+1][j]);

        cout << table[xl][yl] << endl;
    }

    return 0;
}

C++: 
#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;

int dp[1001][1001];
int main() {
    int q;
    cin>>q;
    int ans[150] = {0};
    for (int i = 0; i < q; ++i) {
        memset(dp, 0, sizeof(dp));
        string x, y;
        cin>>x>>y;
        int xlen = x.length();
        int ylen = y.length();
        for(int ix = 0; ix < xlen; ++ix) {
            for(int iy = 0; iy < ylen; ++iy) {
                if (x[ix] == y[iy]) {
                    dp[ix + 1][iy + 1] = max(max(dp[ix][iy] + 1, dp[ix + 1][iy]), dp[ix][iy+1]);
                } else {
                    dp[ix + 1][iy + 1] = max(dp[ix + 1][iy], dp[ix][iy+1]);
                }
            }
        }
        ans[i] = dp[xlen][ylen];
    }

    for(int i = 0; i < q; ++i) {
        cout<<ans[i]<<endl;
    }

}