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>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>	// require sort next_permutation count __gcd reverse etc.
#include <cstdlib>	// require abs exit atof atoi 
#include <cstdio>		// require scanf printf
#include <functional>
#include <numeric>	// require accumulate
#include <cmath>		// require fabs
#include <climits>
#include <limits>
#include <cfloat>
#include <iomanip>	// require setw
#include <sstream>	// require stringstream 
#include <cstring>	// require memset
#include <cctype>		// require tolower, toupper
#include <fstream>	// require freopen
#include <ctime>		// require srand
#define rep(i,n) for(int i=0;i<(n);i++)
#define ALL(A) A.begin(), A.end()

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

int dp[1005][1005];

int main()
{
	ios_base::sync_with_stdio(0);
	int n; cin >> n;
	while (n-- ){
		memset (dp, 0, sizeof (dp ) );
		string s, t;
		cin >> s >> t;
		int n = s.length();
		int m = t.length();
		rep (j, m ) if (s[0] == t[j] ) dp[0][j] = 1;
		rep (i, n ) if (s[i] == t[0] ) dp[i][0] = 1;

		for (int i = 1; i < n; i++ ){
			for (int j = 1; j < m; j++ ){
				dp[i][j] = max (dp[i][j], dp[i-1][j-1] + (s[i] == t[j] ? 1 : 0 ) );
				dp[i][j] = max (dp[i][j], dp[i-1][j] );
				dp[i][j] = max (dp[i][j], dp[i][j-1] );
			} // end for
		} // end for
/*
		rep (i, n ){
			rep (j, m ){
				printf ("%3d", dp[i][j] );
			} // end rep
			printf ("\n" );
		} // end rep
*/		
		int res = dp[n-1][m-1]; 		
		cout << res << endl;
	} // end loop

//	printf ("%d\n", res );
		
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define FOR(i,a,b) for(int i=a;i<=b;i++)
#define FORD(i,a,b) for(int i=a;i>=b;i--)
#define ALL(a)  (a).begin(),(a).end()
#define SZ(a) int((a).size())
#define SORT(c) sort((c).begin(),(c).end())
#define MEMSET(v, h) memset((v), h, sizeof(v))
#define sqr(x) ((x) * (x))
#define bit(n) (1LL<<(n))
#define pcnt(x) __builtin_popcountll(x)
#define PB push_back
#define MP make_pair
#define endl "\n"
using Edge = pair<int,int>;
using Graph = vector<vector<Edge>>;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
// ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
// ll lcm(ll a,ll b){return a/gcd(a,b)*b;}



int main() {
  int q; cin >> q;
  FOR(i,0,q-1){
    int dp[1010][1010];
    string a,b; cin >> a >> b;
    MEMSET(dp,0);
    FOR(j,1,a.length()){
      FOR(k,1,b.length()){
        if(a[j-1] == b[k-1]) dp[j][k] = dp[j-1][k-1] + 1;
        else dp[j][k] = max(dp[j-1][k],dp[j][k-1]);
      }
    }
    // FOR(i,1,a.length()){
    //   FOR(j,1,b.length()){
    //     cout << dp[i][j] << " ";
    //   }
    //   cout << "\n";
    // }
    cout << dp[a.length()][b.length()] << "\n";
  }
}

C++: #include <iostream>

using namespace std;

/**
 *  lcs(m,n) = 
 *  if x[m] == y[n] lcs[m-1,n-1]+1
 *  max(lcs[m-1,n],lcs[m,n-1])
 *
 */

string x, y;

int lcs(int m, int n)
{
	if (m == -1 || n== -1) return 0;
	if (x[m] == x[n]) return lcs(m-1,n-1) + 1;
	int xx = lcs(m-1,n);
	int yy = lcs(m,n-1);
	return xx > yy ? xx : yy;
}

int main()
{
	int n = 0;
	x.resize(150);
	y.resize(150);
	cin >> n; 
	for (int i=0;i<n;i++)
	{
		cin >> x;
		cin >> y;
		return lcs(x.size()-1, y.size()-1);
	}
}

C++: #include<stdio.h>
#include<string.h>
 
char X[1001],Y[1001];
 
int LCS_Length(void){
  int i,j;
  int m = strlen(X);
  int n = strlen(Y);
  int c[m+1][n+1];
 
  for(i=1 ; i<=m ; i++) c[i][0] = 0;
  for(j=0 ; j<=n ; j++) c[0][j] = 0;
   
  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 if(c[i-1][j] >= c[i][j-1]) c[i][j] = c[i-1][j];
      else c[i][j] = c[i][j-1];
    }
  }
  return c[m][n]; 
}
 
main(){
  int i,n;
  scanf("%d",&n);
  for(i=0 ; i<n ; i++){
    scanf("%s%s",X,Y);
    printf("%d\n",LCS_Length());
  }
  return 0;
}

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

using namespace std;
static const int N = 100;
static const int INFTY = (1<<21);

int n, M[N][N];
int d[N];

void bfs(int s) {
    queue<int> q;
    q.push(s);
    for(int i = 0; i < n; i++) d[i] = INFTY;
    d[s] = 0;
    int u;
    while( !q.empty() ) {
        u = q.front(); q.pop();
        for (int v = 0; v < n; v++) {
            if( M[u][v] == 0 || d[v]!= INFTY ) continue;
            d[v] = d[u] + 1;
            q.push(v);
        }
    }
    for (int i = 0; i < n; i++) {
        cout << i+1 << " " << (d[i] == INFTY ? (-1) : d[i]) << endl;
    }
}

int main() {
    int u, k, v;

    cin >> n;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            M[i][j] = 0;
        }
    }

    for(int i = 0; i < n; i++) {
        cin >> u >> k;
        u--;
        for (int j = 0; j < k; j++) {
            cin >> v;
            v--;
            M[u][v] = 1;
        }
    }

    bfs(0);

    return 0;
}

C++: #include<stdio.h>
#include<string.h>
    
int LCS(char *X, char *Y){
  int i,j,m,n,c[1001][1001];
  m = strlen(X);
  n = strlen(Y);
      
  for(i=0; i<m; i++){
    c[i][0] = 0;
  }
  for(j=0; j<n; j++){
    c[0][j] = 0;
  }
    
  for(i=1;i<m+1;i++){
    for(j=1;j<n+1;j++){
      if (X[i-1]==Y[j-1]) c[i][j]=c[i-1][j-1]+1;
      else if (c[i-1][j]>=c[i][j-1]) c[i][j]=c[i-1][j];
      else c[i][j]=c[i][j-1];
    }
  }
  return c[i-1][j-1];
}
    
int main(){
  int i, q;
  char X[1001], Y[1001];
      
  scanf("%d", &q);
  for(i=0; i<q; i++){
    scanf("%s", X);
    scanf("%s", Y);
    printf("%d\n", LCS(X, Y));
    
  }
  return 0;
}