UVA624(01背包 ＋ 路径打印)

题目的意思就就是给你一个值，在给你几个数字．用这些数字凑出最接近这个值的组合．简单０１背包　＋　路径打印．

路径打印时可以根据　ｆ［ｉ］［ｊ］　＝＝　f [ i - 1] [ j ] 的话，这个数就没有被选择．

从后往前找：

ＡＣ代码;

#include<stdio.h>
#include<string.h>
const int N = 1000;
const int M = 25;
int track[M];
int f[M][N * M];
int vis[M];
int n;
int sum;
int dp() {
for (int i =  1 ; i <= n ; i++) {
for (int j = 0  ; j <= sum ;j++) {
f[i][j] = f[i - 1][j];
if (j >= track[i]) {
int temp =f[i - 1][j - track[i]] + track[i];
f[i][j] = f[i][j] > temp ? f[i][j] : temp;
}
}
}
}
void print() {
int j = sum;
for (int i = n ; i >= 1  ;i--) {
if (f[i][j] != f[i - 1][j]) {
printf("%d " ,track[i]);
j -= track[i];
}
}

}
int main () {
while(~scanf("%d%d",&sum,&n)) {
for (int i = 1 ; i <= n ;i++) {
scanf("%d", &track[i]);
}
memset(f , -1 ,sizeof(f));
memset(vis , 0 ,sizeof(vis));
for (int i =  0 ; i < N * M;i++) {
f[0][i] = 0;
}
dp();
print();
printf("sum:%d\n" ,f
[sum]);
}
}