#include <iostream>using namespace std;int lps(string seq, int i, int j){ int len1, len2; if (i == j) return 1; if (i > j) return 0; if (seq[i] == seq[j]) return lps(seq, i + 1, j - 1) + 2; len1 = lps(seq, i, j - 1); len2 = lps(seq, i + 1, j); if (len1 > len2) return len1; return len2;}int main(){ string seq = "acmerandacm"; int n = seq.size(); cout << lps(seq, 0, n - 1) << endl; return 0;}输出：_________