【HDOJ】1114 Piggy-Bank
DP，先将coins按照重量排序可以优化。
1 #include <stdio.h> 2 #include <stdlib.h> 3 4 #define MAXNUM 10005 5 #define COINNUM 505 6 #define MAXVAL 0x7fffffff 7 #define MYMIN(a, b) a<b ? a:b 8 9 typedef struct { 10 int weight, val; 11 } coin_st; 12 13 coin_st coins[COINNUM]; 14 int dp[MAXNUM]; 15 int e, f; 16 17 int comp(const void *a, const void *b) { 18 return ((coin_st*)a)->weight - ((coin_st*)b)->weight; 19 } 20 21 int main() { 22 int case_n, n; 23 int i, j, left; 24 25 scanf("%d", &case_n); 26 dp[0] = 0; 27 while (case_n--) { 28 scanf("%d %d", &e, &f); 29 scanf("%d", &n); 30 for (i=0; i<n; ++i) 31 scanf("%d %d", &coins[i].val, &coins[i].weight); 32 qsort(coins, n, sizeof(coin_st), comp); 33 34 for (i=1; i<=f-e; ++i) { 35 dp[i] = MAXVAL; 36 for (j=0; j<n; ++j) { 37 left = i-coins[j].weight; 38 if (left<0) 39 break; 40 if (dp[left]!=MAXVAL && dp[left]+coins[j].val < dp[i]) 41 dp[i] = dp[left]+coins[j].val; 42 } 43 } 44 if (dp[f-e] == MAXVAL) 45 printf("This is impossible.\n"); 46 else 47 printf("The minimum amount of money in the piggy-bank is %d.\n", dp[f-e]); 48 } 49 50 return 0; 51 }
