【HDOJ】2159 FATE

DP+贪心优化。

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>

 #define MAXNUM 105

 typedef struct {
     int exp, deg;
 } info_st;

 info_st infos[MAXNUM];
 int dp[MAXNUM][MAXNUM];
 int n, m, k, s;

 int comp(const void *a, const void *b) {
     info_st *p = (info_st *)a;
     info_st *q = (info_st *)b;

     if (p->deg == q->deg)
         return q->exp - p->exp;
     else
         return p->deg - q->deg;
 }

 int mymax(int a, int b) {
     return a>b ? a:b;
 }

 int main() {
     int i, j, p, exp, deg;

     while (scanf("%d%d%d%d", &n, &m, &k, &s) != EOF) {
         for (i=; i<k; ++i)
             scanf("%d %d", &infos[i].exp, &infos[i].deg);

         memset(dp, , sizeof(dp));
         qsort(infos, k, sizeof(info_st), comp);

         for (i=; i<k; ++i) {
             exp = infos[i].exp;
             deg = infos[i].deg;
             if (i && deg == infos[i-].deg) {
                 continue;
             }
             for (j=; j<=s; ++j) {
                 for (p=deg; p<=m; ++p) {
                     dp[p][j] = mymax(dp[p][j], dp[p-deg][j-]+exp);
                 }
             }
         }

         for (i=; i<=m; ++i) {
             if (dp[i][s] >= n)
                 break;
         }

         if (i <= m)
             printf("%d\n", m-i);
         else
             printf("-1\n");
     }

     return ;
 }