46 lines
1.2 KiB
C++
46 lines
1.2 KiB
C++
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#include <cassert>
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#include <string>
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#include <vector>
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class Solution {
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auto dp_helper(const std::string &t1, const std::string &t2,
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std::vector<int> &dp, int i, int j) -> int {
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if (i < 0 || j < 0) {
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return 0;
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}
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auto idx = i * t2.size() + j;
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if (dp[idx] != -1) {
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return dp[idx];
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}
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if (t1[i] == t2[j]) {
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dp[idx] = 1 + dp_helper(t1, t2, dp, i - 1, j - 1);
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} else {
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dp[idx] = std::max(dp_helper(t1, t2, dp, i - 1, j),
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dp_helper(t1, t2, dp, i, j - 1));
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}
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return dp[idx];
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}
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public:
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auto longestCommonSubsequence(const std::string &text1,
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const std::string &text2) -> int {
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int m = text1.size();
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int n = text2.size();
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std::vector<int> dp(m * n, -1);
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return dp_helper(text1, text2, dp, m - 1, n - 1);
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}
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};
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int main() {
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Solution s;
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assert(s.longestCommonSubsequence("abcde", "ace") == 3);
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assert(s.longestCommonSubsequence("abc", "abc") == 3);
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assert(s.longestCommonSubsequence("abc", "def") == 0);
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return 0;
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}
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