Go: package main

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

var (
	nstr   func() string
	stdout *bufio.Writer
)

func init() {
	nstr = newReadString(os.Stdin)
	stdout = bufio.NewWriter(os.Stdout)
}

func main() {
	defer stdout.Flush()

	n := nint()
	xList := make([]string, n)
	yList := make([]string, n)

	for i:=0;i<n ;i++  {
		xList[i] = nstr()
		yList[i] = nstr()
	}

	for i := 0; i<n	; i++  {
		fmt.Println(lcs(xList[i], yList[i]))
	}

}

func lcs(x string, y string) int{
	var m = len(x)
	var n = len(y)

	c := make([][]int, m+1)
	for i:= range c{
		c[i] = make([]int, n+1)
	}
	for i:=	1;i<=m ;i++  {
		for j:=1;j<=n ;j++  {
			if x[i-1] == y[j-1]{
				c[i][j] = c[i-1][j-1] + 1
			}else{
				c[i][j] = int(math.Max(float64(c[i-1][j]), float64(c[i][j-1])))
			}


		}
	}
	return c[m][n]

}


func newReadString(ior io.Reader) func() string {
	r := bufio.NewScanner(ior)
	r.Buffer(make([]byte, 1024), int(1e+11))
	r.Split(bufio.ScanWords)

	return func() string {
		if !r.Scan() {
			panic("Scan failed")
		}
		return r.Text()
	}
}

func nint64() int64 {
	i, err := strconv.ParseInt(nstr(), 0, 64)
	if err != nil {
		panic(err.Error())
	}
	return i
}

func nint() int {
	return int(nint64())
}

func getIntSlice(n int) []int {
	b := make([]int, n)
	for i := 0; i < n; i++ {
		b[i] = nint()
	}
	return b
}

func getStringSlice(n int) []string {
	b := make([]string, n)
	for i := 0; i < n; i++ {
		b[i] = nstr()
	}
	return b
}

func gcd(x, y int) int {
	if y == 0 {
		return x
	}
	return gcd(y, x%y)
}

func lcm(x, y int) int {
	return x * y / gcd(x, y)
}

func contains(s []int, e int) bool {
	for _, a := range s {
		if a == e {
			return true
		}
	}
	return false
}

func bin(i int, prefix bool) string {
	i64 := int64(i)

	if prefix {
		return "0b" + strconv.FormatInt(i64, 2)
	} else {
		return strconv.FormatInt(i64, 2)
	}
}

func strReverse(s string) string {
	runes := []rune(s)
	for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
		runes[i], runes[j] = runes[j], runes[i]
	}

	return string(runes)
}

C++: #include<iostream>
#include<vector>
#include<string>
using namespace std;
const int NIL = -1;
void SearchMaxSubString(string & a,string & b,
						vector<vector<int> > & maxlen,
						int s,
						int t)
{
	int lengthAB = 0;
	if (a[s] == b[t]) {
		lengthAB++;
		if ((s+1) < (int)a.size() && (t+1) < (int)b.size()) {
			if (maxlen[s+1][t+1] == NIL) {
				SearchMaxSubString(a,b,maxlen,s+1,t+1);
			}
			lengthAB += maxlen[s+1][t+1];
		}
		maxlen[s][t] = lengthAB;
	}
	else {
		int lengthA = 0;
		int lengthB = 0;
		if ((s+1) < (int)a.size()) {
			if (maxlen[s+1][t] == NIL) {
				SearchMaxSubString(a,b,maxlen,s+1,t);
			}
			lengthA = maxlen[s+1][t];
		}
		if ((t+1) < (int)b.size()) {
			if (maxlen[s][t+1] == NIL) {
				SearchMaxSubString(a,b,maxlen,s,t+1);
			}
			lengthB = maxlen[s][t+1];
		}
		maxlen[s][t] = std::max(lengthA,lengthB);
	}
}

int main(){
	int n;
	cin >> n;
	for(; n > 0; --n) {
		string a,b;
		cin >> a >> b;
		vector<vector<int> > maxlen;
		maxlen.resize(a.size());
		for(unsigned int i=0;i<a.size();++i) {
			maxlen[i].resize(b.size());
			for(unsigned j=0;j<maxlen[i].size();++j){
				maxlen[i][j] = NIL;
			}
		}
		SearchMaxSubString(a,b,maxlen,0,0);
		cout << maxlen[0][0] << std::endl;
	}
	return 0;
}

C++: #include<iostream>
#include<string>
int main(){
  int q;
  std::cin>>q;
  int i,j,k;
  std::string x,y;
  int a[1001][1001];
  int knum[q];
  for(i=0; i<1001; i++){
    for(j=0; j<1001; j++){
      a[i][j]=0;
    }
  }
  for(k=0; k<q; k++){
    std::cin>>x;
    std::cin>>y;
    for(i=1; i<x.size()+1; i++){
      for(j=1; j<y.size()+1; j++){
	if(x[i-1]==y[j-1]){
	  a[i][j]=a[i-1][j-1]+1;
	}else{
	  if(a[i-1][j]>a[i][j-1]){
	    a[i][j]=a[i-1][j];
	  }else{
	    a[i][j]=a[i][j-1];
	  }
	}
      }	
    }
    knum[k]=a[x.size()][y.size()];
  }
  for(k=0; k<q; k++){
    std::cout<<knum[k]<<"\n";
  }
  return 0;
}

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

static const int N = 1000;

int lcs(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 = 0; 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 <bits/stdc++.h>
using namespace std;
typedef long long ll;
//template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
//template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
 
/* attention
    long longのシフト演算には気をつけよう
    タイポした時のデバッグが死ぬほどきつくなるので変数名は最低3字くらい使った方がいいかも
*/

int lcm(string s, string t, vector<vector<int>> dp){
    int m = s.size();
    int n = t.size();
    int maxl = 0;
    s = " " + s;
    t = " " + t;
    for(int i=0; i<=m; i++) dp[i][0] = 0;
    for(int j=0; j<=n; j++) dp[0][j] = 0;

    for(int i=1; i<=m; i++){
        for(int j=1; j<=n; j++){
            if(s[i] == t[j]) dp[i][j] = dp[i-1][j-1]+1;
            else dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
            maxl = max(maxl, dp[i][j]);
        }
    }

    return maxl;
}

int main(){
    vector<vector<int>> dp(1001, vector<int>(1001, 0));

    int n; cin >> n;
    for(int i=0; i<n; i++){
        string s, t; cin >> s >> t;
        cout << lcm(s, t, dp) << endl;
    }
}

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

int lcs(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 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<string>
#include<algorithm>
using namespace std;

int lcs(string str1, string str2) {
	int n1 = str1.size();
	int n2 = str2.size();
	int A[n1 + 1][n2 + 1];
	for (int i = 0; i <= n1; i++) A[i][0] = 0;
	for (int j = 1; j <= n1; j++) A[0][j] = 0;

	for (int i = 1; i <= n1; i++) {
		for (int j = 1; j <= n2; j++) { 
			if (str1[i - 1] == str2[j - 1]) {
				A[i][j] = A[i - 1][j - 1] + 1; 
			} else {
				A[i][j] = max(A[i - 1][j], A[i][j - 1]); 
			}
		}
	}
	return A[n1][n2];
}

int main() {
	int n;
	string str1, str2;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> str1 >> str2;
		cout << lcs(str1, str2) << endl;
	}
	return 0;
}