Go: package main

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

type Position struct {
	X int
	Y int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}
	for i := 0; i < n; i++ {
		strX := nextText(sc)
		strY := nextText(sc)
		fmt.Println(calcLcs(strX, strY))
	}
}

func calcLcs(strX, strY string) int {
	return lcs(strX, strY, Position{0, 0}, make(map[Position]int))
}

func lcs(strX string, strY string, position Position, memo map[Position]int) int {
	if position.X >= len(strX) || position.Y >= len(strY) {
		return 0
	}
	if v, ok := memo[position]; ok {
		return v
	}
	if strX[position.X] == strY[position.Y] {
		result := lcs(strX, strY, Position{position.X + 1, position.Y + 1}, memo)
		memo[position] = result + 1
		return memo[position]
	} else {
		result1 := lcs(strX, strY, Position{position.X + 1, position.Y}, memo)
		result2 := lcs(strX, strY, Position{position.X, position.Y + 1}, memo)
		var result int
		if result1 > result2 {
			result = result1
		} else {
			result = result2
		}
		memo[position] = result
		return result
	}
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

C++: #define PI 3.14159265359
#define INF 2000000000
#define MAX 500000
#include <map>
#include <algorithm>
#include <vector>
#include <queue>
#include <iostream>
#include <string>
#include <cstring>
#include <cmath>
#include <cstdio>
using namespace std;
typedef long long ll;

void LCS(string X,string Y){
 int c[1000][1000];
 int n=X.length(),m=Y.length();
 for(int i=0;i<=max(n,m);i++){
     c[i][0]=c[0][i]=0;
 }
 for(int i=1;i<=n;i++){
     for(int j=1;j<=m;j++){
         if(X[i]==Y[j])
           c[i][j]=c[i-1][j-1]+1;
         else{
           c[i][j]=max(c[i][j-1],c[i-1][j]);
         }
     }
 }
 cout<<c[n][m]<<endl;
}

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

C++: #include<iostream>
#include<string>
#include<cstring>
#include<algorithm>
#define MAX_N 1000
int dp[MAX_N][MAX_N];
int solve(std::string s,std::string t){
        
        memset(dp,0,sizeof(dp));
        int n,m;
        n=s.size(),m=t.size();
        for(int i=0;i<n;i++){
                for(int j=0;j<m;j++){
                        if(s[i]==t[j])
                                dp[i+1][j+1]=dp[i][j]+1;
                        else
                                dp[i+1][j+1]=std::max(dp[i][j+1],dp[i+1][j\
]);
                }
        }
        return dp[n][m];
}

int main(){
        int q;
        std::cin>>q;
        for(int i=0;i<q;i++){
                std::string s,t;
                std::cin >> s>>t;
                std::cout << solve(s,t) << std::endl;
        }
        return 0;
}

C++: #pragma GCC optimize ("O3")

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <queue>
#include <set>
#include <algorithm>
#include <numeric>
#include <string>
using namespace std;

using QWORD  = uint64_t;
using SQWORD = int64_t;
using DWORD  = uint32_t;
using SDWORD = int32_t;
using WORD   = uint16_t;
using SWORD  = int16_t;
using BYTE   = uint8_t;
using SBYTE  = int8_t;
using DOUBLE = double;
using FLOAT  = float;

#define MIN_SDWORD (-2147483648)
#define MAX_SDWORD (2147483647)
#define MIN_SBYTE (-128)
#define MAX_SBYTE (127)

#define MIN_SQWORD (0x8000000000000000)
#define MAX_SQWORD (0x7FFFFFFFFFFFFFFF)

#define MAX_QWORD  (0xFFFFFFFFFFFFFFFF)
#define MAX_DWORD  (0xFFFFFFFF)
#define MAX_WORD   (0xFFFF)
#define MAX_BYTE   (0xFF)


#define ArrayLength(a)  (sizeof(a) / sizeof(a[0]))

static inline QWORD MAX(QWORD a, QWORD b) { return a > b ? a : b; }
static inline DWORD MAX(DWORD a, DWORD b) { return a > b ? a : b; }
static inline SDWORD MAX(SDWORD a, SDWORD b) { return a > b ? a : b; }
static inline QWORD MIN(QWORD a, QWORD b) { return a < b ? a : b; }
static inline DWORD MIN(DWORD a, DWORD b) { return a < b ? a : b; }
static inline SDWORD MIN(SDWORD a, SDWORD b) { return a < b ? a : b; }

#define BYTE_BITS   (8)
#define WORD_BITS   (16)
#define DWORD_BITS  (32)
#define QWORD_BITS  (64)

using M_BOOL = bool;
#define M_TRUE (true)
#define M_FALSE (false)
#define DIVISOR (1000000007)

static inline void inputString(char *pcStr)
{
    char *pcCur = pcStr;
    for (;;) {
        char c = getchar();
        if (('\n' == c) || (EOF == c)) {
            break;
        }
        *pcCur = c;
        pcCur++;
    }
    *pcCur = '\0';
}


static inline SQWORD inputSQWORD(void)
{
    SQWORD sqNumber = 0;
    SQWORD sqMultiplier = 1;
    M_BOOL bRead = M_FALSE;
    for (;;) {
        char c = getchar();
        if (!bRead) {
            if ('-' == c) {
                sqMultiplier = -1;
            }
        }
        if (('0' <= c) && (c <= '9')) {
            sqNumber *= 10LL;
            sqNumber += (SQWORD)(c - '0');
            bRead = M_TRUE;
        } else {
            if (bRead) {
                return sqNumber * sqMultiplier;
            }
        }
    }
}


static inline SDWORD inputSDWORD(void)
{
    SDWORD lNumber = 0;
    SDWORD lMultiplier = 1;
    M_BOOL bRead = M_FALSE;
    for (;;) {
        char c = getchar();
        if (!bRead) {
            if ('-' == c) {
                lMultiplier = -1;
            }
        }
        if (('0' <= c) && (c <= '9')) {
            lNumber *= 10;
            lNumber += (c - '0');
            bRead = M_TRUE;
        } else {
            if (bRead) {
                return lNumber * lMultiplier;
            }
        }
    }
}

static inline DOUBLE inputFP(void)
{
    DOUBLE dInt = 0.0;
    DOUBLE dFrac = 0.0;
    DOUBLE dMultiplier = 1.0;
    DWORD dwFpCnt = 0;
    DOUBLE *pdCur = &dInt;
    M_BOOL bRead = M_FALSE;
    for (;;) {
        char c = getchar();
        if (!bRead) {
            if ('-' == c) {
                dMultiplier = -1;
            }
        }
        if ('.' == c) {
            pdCur = &dFrac;
        } else if (('0' <= c) && (c <= '9')) {
            (*pdCur) *= 10;
            (*pdCur) += (DOUBLE)(c - '0');
            bRead = M_TRUE;
            if (pdCur == &dFrac) {
                dwFpCnt++;
            }
        } else {
            if (bRead) {
                return dMultiplier * (dInt + dFrac / (pow((DOUBLE)10.0 , (DOUBLE)dwFpCnt)));
            }
        }
    }
}

#define MAX_STR_LEN (1000)
static void getLongestCommonSubsequence(
    const string &strS1,
    const string &strS2)
{
    /* dp[i+1][j+1]: S1のi文字目, S2のj文字目までで一致する最長の文字数 */
    /**
     *  初期化をさぼるため、dptbl のインデックスをひとつずらしている
     */
    static SDWORD alDpTbl[MAX_STR_LEN + 1];
    static SDWORD alNextDpTbl[MAX_STR_LEN + 1];
    memset(alDpTbl, 0, sizeof(alDpTbl));

    for (SDWORD lIdxS1 = 0; lIdxS1 < strS1.size(); lIdxS1++) {
        alNextDpTbl[0] = 0;
        for (SDWORD lIdxS2 = 0; lIdxS2 < strS2.size(); lIdxS2++) {
            if (strS1[lIdxS1] == strS2[lIdxS2]) {
                alNextDpTbl[lIdxS2+1] = alDpTbl[lIdxS2] + 1;
            } else {
                alNextDpTbl[lIdxS2+1] = max(alDpTbl[lIdxS2+1],
                                                    alNextDpTbl[lIdxS2]);
            }
        }
        memcpy(alDpTbl, alNextDpTbl, sizeof(alDpTbl));
    }

    printf("%d\n", alDpTbl[strS2.size()]);
}

int main()
{
    SDWORD  lNumDataSet = inputSDWORD();
    char acStr1[MAX_STR_LEN + 1];
    char acStr2[MAX_STR_LEN + 1];

    for (SDWORD lIdx = 0; lIdx < lNumDataSet; lIdx++) {
        inputString(acStr1);
        inputString(acStr2);


        string strS1(acStr1);
        string strS2(acStr2);
        getLongestCommonSubsequence(strS1, strS2);
    }

    return 0;
}