题意:求两个序列的最长公共上升子序列。
分析:《算法竞赛进阶指南》P266。
代码:
#include <cstdio>
#include <iostream>
#include <algorithm>
using namespace std;
const int N = 3006;
int n, a[N], b[N], f[N][N];
int main() {
cin >> n;
for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
for (int i = 1; i <= n; i++) scanf("%d", &b[i]);
for (int i = 1; i <= n; i++) {
int val = 0;
for (int j = 1; j <= n; j++) {
f[i][j] = (a[i] == b[j] ? val + 1 : f[i-1][j]);
if (b[j] < a[i]) val = max(val, f[i-1][j]);
}
}
int ans = 0;
for (int j = 1; j <= n; j++) ans = max(ans, f[n][j]);
cout << ans << endl;
return 0;
}