ZOJ 1524 Supermarket

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动态规划

F[i][j]：列表上第i个物品和supermarket里面第ｊ个商品。此时可以花的最小费用。

a[i] == b[j] F[i][j] = min(F[i][j-1], F[i-1][j-1] + p[j])

a[i] != b[j] F[i][j] = F[i][j-1]

初始化为最大值inf

#include <cstdio>#include <cstring>#include <algorithm>using namespace std;#define N 100002#define M 102#define inf 1e10int a[M], b[N], n, m;double p[N], f[2][N];int main() {    while (scanf("%d%d", &m, &n) == 2 && n+m) {        for (int i=1; i<=m; i++) scanf("%d", &a[i]);        int cur = 1;        f[cur][0] = inf;        for (int i=1; i<=n; i++) {            scanf("%d%lf", &b[i], &p[i]);            if (b[i] == a[1]) f[cur][i] = min(f[cur][i-1], p[i]);            else f[cur][i] = f[cur][i-1];        }        for (int i=2; i<=m; i++) {            cur = 1 - cur;            for (int j=0; j<=n; j++) f[cur][j] = inf;            for (int j=1; j<=n; j++) {                if (a[i] == b[j]) f[cur][j] = min(f[cur][j-1], f[1-cur][j-1]+p[j]);                else f[cur][j] = f[cur][j-1];            }        }        if (f[cur][n] < inf) printf("%.2lf\n", f[cur][n]);        else printf("Impossible\n");    }    return 0;}