Go: package main

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

//Util
func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

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

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

func absInt(a int) int {
	if a >= 0 {
		return a
	} else {
		return -a
	}
}

func absFloat64(a float64) float64 {
	if a >= 0 {
		return a
	} else {
		return -a
	}
}

func minFloat64(a, b float64) float64 {
	if a > b {
		return b
	} else {
		return a
	}
}

func str2Int(s string) int {
	n, _ := strconv.Atoi(s)
	return n
}

//Main
var sc = bufio.NewScanner(os.Stdin)
var q int
var X, Y string

func lcs(X, Y string) int {
	lenX := len(X)
	lenY := len(Y)
	dp := make([][]int, lenX+1)
	for i := 0; i < lenX+1; i++ {
		dp[i] = make([]int, lenY+1)
	}

	res := 0
	for i := 1; i < lenX+1; i++ {
		for j := 1; j < lenY+1; j++ {
			if X[i-1] == Y[j-1] {
				dp[i][j] = dp[i-1][j-1] + 1
			} else {
				dp[i][j] = maxInt(dp[i-1][j], dp[i][j-1])
			}
			//fmt.Println(dp)
			res = maxInt(res, dp[i][j])
		}

	}
	return res
}

func main() {
	sc.Split(bufio.ScanWords)
	q = nextInt()

	for i := 0; i < q; i++ {
		X = nextStr()
		Y = nextStr()

		fmt.Println(lcs(X, Y))
	}
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define MM 1000000000
#define MOD MM+7
#define MAX 301000
#define MAP 110
#define initial_value -1
#define Pair pair<int,int>
#define chmax(a,b) (a<b ? a=b:0)
#define chmin(a,b) (a>b ? a=b:0)
ll INF = 1e18;
int dx[4] = {-1,0,1,0};
int dy[4] = {0,-1,0,1};
//union_find
int par[100];
int depth[100];
ll N;
ll x[20],c[20],v[20];
string s,t;

int lcs(string x, string y){
    int dp[1010][1010];
    int m = x.size();
    int n = y.size();
    int mx = 0;
    x = ' ' + x;
    y = ' ' + y;
    for(int i = 0; i <= m; i++){
        for(int j = 0; j <= n; j++){
            dp[i][j] = 0;
        }
    }
    for(int i = 1; i <= m; i++){
        for(int j = 1; j <= n; j++){
            if(x[i] == y[i]){
                dp[i][j] = dp[i-1][j-1] + 1;
            } else {
                dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
            }
            mx = max(mx, dp[i][j]);
        }
    }
    return mx;
}
int main(){
    cin >> N;
    for(int i = 0; i < N; i++){
        cin >> s >> t;
        cout << lcs(s,t) << endl;
    }
}

C++: #include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <climits>
#include <cfloat>
#include <functional>
#include <cctype>

using namespace std;

#define REP(i,n) for(int i = 0; i < (int)n; ++i)

string X, Y;

void solve(int x_size, int y_size)
{
	vector< vector<int> > dp(x_size + 1, vector<int>(y_size + 1));

	for(int i = 0; i < x_size; ++i) {
		for(int j = 0; j < y_size; ++j) {
			if(X[i] == Y[j]) {
				dp[i + 1][j + 1] = dp[i][j] + 1;
			}
			else {
				dp[i + 1][j + 1] = max(dp[i][j + 1], dp[i + 1][j]);
			}
		}
	}

	cout << dp[X.size()][Y.size()] << endl;
}

int main()
{
	std::ios::sync_with_stdio(false);
	std::cin.tie(0);

	int n;
	cin >> n;
	REP(i, n) {
		cin >> X >> Y;
		solve(X.size(), Y.size());
	}
	return 0;
}

C++: #include<iostream>
#include<string>
#include <algorithm>
using namespace std;
string X;
string Y;
int lcs[1002][1002];
int calLcs() {
	int i = 1;
	int j = 1;
	int m = Y.size();
	int n = X.size();
	for (i = 1; i <= n; i++) {
		for (j = 1; j <= m; j++) {
			if (X[i - 1] == Y[j - 1]) {
				lcs[i][j] = lcs[i - 1][j - 1] + 1;
			}
			else {
				lcs[i][j] = max(lcs[i - 1][j], lcs[i][j - 1]);
			}
		}
	}
	return lcs[n][m];
}
int main() {
	int n;
	cin >> n;
	while (n--) {
		cin >> X;
		cin >> Y;
		cout << calLcs() << endl;
	}
}

C++: #include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
int main(){
  char str1[1000],str2[1000];
  int LCS[1000][1000]={0};
  int length1,length2;
  int n;
  std::ios::sync_with_stdio(false);
  scanf("%d",&n);
  for(int s=1;s<=n;s++){
   while(cin>>str1>>str2){
     length1=strlen(str1);
     length2=strlen(str2);
     for(int i=0;i<=length1-1;i++){
       LCS[i][0]=0;
     }
     for(int j=0;j<=length2-1;j++){
       LCS[0][j]=0;
     }
     for(int i=1;i<=length1;i++){
       for(int j=1;j<=length2;j++){
         if(str1[i-1]==str2[j-1]) {
           LCS[i][j]=LCS[i-1][j-1]+1;
         }
         else LCS[i][j]=max(LCS[i-1][j],LCS[i][j-1]);
       }
     }
     printf("%d\n",LCS[length1][length2]);
   }
 }
   return 0;
}

C++: q = int(input())
for i in range(q):
    x = input()
    y = input()
    n = len(x)
    m = len(y)
    dp = [0]*((n+1)*(m+1))
    for i in range(n):
        for j in range(m):
            a = (n+1)*(j+1)+i+1
            if x[i] == y[j]:
                b = (n+1)*j+i
                dp[a] = dp[b]+1
            else:
                c = (n+1)*j+i+1
                d = (n+1)*(j+1)+i
                dp[a] = max(dp[c],dp[d])
    print(dp[-1])

C++: #include <iostream>
#include <cmath>
#include <vector>

constexpr int MAX = 1000;
char ls[MAX];
char rs[MAX];
int table[MAX + 1][MAX + 1];


void calc_lcs() {
    scanf("%s", ls);
    scanf("%s", rs);
    int l_len = int(std::strlen(ls));
    int r_len = int(std::strlen(rs));
    for (int i = 0; i < l_len; i++) {
        table[i][0] = 0;
    }
    for (int i = 0; i < r_len; i++) {
        table[0][i] = 0;
    }

    for (int l_i = 1; l_i < l_len + 1; l_i++) {
        for (int r_i = 1; r_i < r_len + 1; r_i++) {
            if (ls[l_i - 1] == rs[r_i - 1]) {
                table[l_i][r_i] = table[l_i - 1][r_i - 1] + 1;
            } else {
                table[l_i][r_i] = std::max(table[l_i][r_i - 1], table[l_i - 1][r_i]);
            }
        }
    }
    std::cout << table[l_len][r_len] << std::endl;
}

int main() {
    int N;
    scanf("%d", &N);
    for (int i = 0; i < N; i++) {
        calc_lcs();
    }
}

C++: /*
** Longest Common Subsequence
*/

# include <cstdio>
# include <cstring>
# include <algorithm>
using namespace std;

const int MAX = 1000 + 5;

char s1[MAX], s2[MAX];
int c[MAX][MAX];

int lcs() {
    int m = strlen(s1);
    int n = strlen(s2);
    c[0][0] = 0;
    int maxl = 0;
    for (int i = 0; i < m; i++) {
        c[i][0] = 0;
    }
    for (int i = 0; i < n; i++) {
        c[0][i] = 0;
    }

    for (int i = 0; i < m; i++) {
        for (int j = 0; j < n; j++) {
            if (s1[i] == s2[j]) {
                c[i][j] = c[i - 1][j - 1] + 1;
            }
            else {
                c[i][j] = max(c[i][j - 1], c[i - 1][j]);
            }
            maxl = max(maxl, c[i][j]);
        }
    }

    return maxl;
}

void solve() {
    int n;
    scanf("%d", &n);
    while (n--) {
        scanf("%s %s", s1, s2);
        printf("%d\n", lcs());
    }
}

int main() {
    // freopen("infile", "r", stdin);
    // freopen("outfile", "w", stdout);
    solve();
    return 0;
}