7 4 3 4 1 3 0 0 0
NO 3
#include <stdio.h>
#include <string.h>
#include <queue>
#define maxn 102
using std::queue;
int s, n, m;
bool vis[maxn][maxn][maxn];
struct Node{
int a[3], step;
} cup;
bool del(Node& tmp, int from, int to)
{
if(!tmp.a[from] || tmp.a[to] == cup.a[to]) return 0;
int t = tmp.a[from] + tmp.a[to];
if(t >= cup.a[to]){
tmp.a[to] = cup.a[to];
tmp.a[from] = t - cup.a[to];
}else{
tmp.a[to] = t;
tmp.a[from] = 0;
}
if(vis[tmp.a[0]][tmp.a[1]][tmp.a[2]]) return 0;
return vis[tmp.a[0]][tmp.a[1]][tmp.a[2]] = 1;
}
void BFS()
{
queue<Node> Q;
int i, j;
Node now, tmp;
now.a[0] = s << 1; now.a[1] = now.a[2] = 0;
now.step = 0;
Q.push(now);
while(!Q.empty()){
now = Q.front(); Q.pop();
for(i = 0; i < 3; ++i){
for(j = 0; j < 3; ++j){
if(i != j){
tmp = now;
++tmp.step;
if(del(tmp, i, j)){
if(tmp.a[0] == s && tmp.a[1] == s || tmp.a[0] == s && tmp.a[2] == s || tmp.a[1] == s && tmp.a[2] == s){
printf("%d\n", tmp.step); return;
}
Q.push(tmp);
}
}
}
}
}
printf("NO\n");
}
int main()
{
while(scanf("%d%d%d", &s, &n, &m), s||n||m){
if(s & 1){
printf("NO\n"); continue;
}
memset(vis, 0, sizeof(vis));
cup.a[0] = s; cup.a[1] = n, cup.a[2] = m;
s >>= 1; BFS();
}
return 0;
}HDU1495 非常可乐 【BFS】,布布扣,bubuko.com
原文：http://blog.csdn.net/chang_mu/article/details/38404931