备忘录和递归解决背包问题

#include <stdio.h>#include <limits.h>int n, M;#define MAX 3407#define MMAX 12880int w[MAX+1];int d[MAX+1];int mem[MAX+1][MMAX+1];int Max(int a, int b){return a > b ? a : b;}// 考虑index为n的。int Value(int *w, int *d, int n, int M){if (n == 0) {if (M >= w[0])return d[0];elsereturn 0;}if (M - w[n] >= 0) {return Max(Value(w, d, n - 1, M), Value(w, d, n - 1, M - w[n-1]) + d[n]);} else {return Value(w, d, n - 1, M);}}// memoryvoid Init(){int i, j;for (i = 0;i < MAX+1; ++i) {for (j = 0; j < MMAX + 1; ++j) {mem[i][j] = INT_MIN;}}}int Value2(int *w, int *d, int n, int M){if (mem[n][M] != INT_MIN)return mem[n][M];if (n == 0) {if (w[0] <= M) {mem[n][M] = d[0];} else {mem[n][M] = 0;}return mem[n][M];}if (w[n] <= M) {mem[n][M] = Max(Value2(w, d, n - 1, M - w[n]) + d[n], Value2(w, d, n - 1, M));} else {mem[n][M] = Value2(w, d, n - 1, M);}return mem[n][M];}int main(){int i;scanf("%d%d", &n, &M);for (i = 0; i < n; ++i) {scanf("%d%d", &w[i], &d[i]);}Init();printf("%d/n", Value2(w, d, n - 1, M));return 0;}