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class Solution {
public:
string a, b;
int dp[1005][1005];
const int INF = 2e8;
int rec(int i, int j) {
    if(i == -1) {
        return 0;
    }
    if(j == -1) {
        return 0;
    }
    if(dp[i][j] != -1) {
        return dp[i][j];
    }
    int res = -INF;
    if(a[i] == b[j]) {
        res = max(res, rec(i - 1, j - 1) + 1);
    }
    res = max(res, rec(i - 1, j));
    res = max(res, rec(i, j - 1));
    return dp[i][j] = res;
}
    int longestCommonSubsequence(string text1, string text2) {
        a = text1;
        b = text2;
    vector<vector<int>> dp(a.size() + 1, vector<int>(b.size() + 1, 0));
    int res = 0;
    for(int i = 1; i <= a.size(); i++) {
        for(int j = 1; j <= b.size(); j++) {
            if(a[i - 1] == b[j - 1]) {
                dp[i][j] = max(dp[i][j], dp[i - 1][j - 1] + 1);
            }
            dp[i][j] = max(dp[i][j], dp[i - 1][j]);
            dp[i][j] = max(dp[i][j], dp[i][j - 1]);
            res = max(res, dp[i][j]);
        }
    }
    return res;
    }
};