POJ 2127 Greatest Common Increasing Subsequence

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Greatest Common Increasing Subsequence

原题：Greatest Common Increasing Subsequence
题意：给出两个序列a、b，求最长公共递增子序列。
解法：dp，因为数据范围比较小，我用的是二维，f[i][j]表示a,b到i,j的最长公共递增子序列，然后转移叫好了

#include <iostream>using namespace std;#include <stdio.h>long long a[1000], b[1000], pre[1000][1000][2], maxa[1000];int n, m, ans, x, y;int f[1000][1000] = {0};long long d[1000] = {0};int max(int x, int y) {    if (x > y) return x;    return y;}int main() {    cin >> n;    for (int i = 1; i <= n; i++)        cin >> a[i];    cin >> m;    for (int i = 1; i <= m; i++) {        cin >> b[i];    }    ans = 0;    for (int i = 1; i <= n; i++)        for (int j = 1; j <= m; j++) {            if (a[i] == b[j]) {                f[i][j] = 1;                for (int k = 1; k < i; k++) if (maxa[k]+1 > f[i][j] && a[k] < a[i]) {                    for (int l = 1; l < j; l++) if (a[k] == b[l] && f[k][l]+1 > f[i][j]) {                        f[i][j] = f[k][l]+1;                    }                }                if (f[i][j] > ans) {                    ans = f[i][j];                    x = i;                    y = j;                }                if (f[i][j] > maxa[i]) maxa[i] = f[i][j];            }        }    if (ans == 0) cout << 0 << endl;    else {        cout << ans << endl;        while (1) {            d[++d[0]] = a[x];            ans--;            if (ans == 0) break;            while (1) {                x--;                bool flag = false;                int j;                for (j = y-1; j >= 1; j--)                    if (a[x] == b[j] && f[x][j] == ans && a[x] < d[d[0]]) {                        flag = true;                        break;                    }                if (flag) {                    y = j; break;                }            }        }        for (int i = d[0]; i > 1; i--) cout << d[i] << " ";        cout << d[1] << endl;    }}

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