HDOJ 1495 非常可乐 【bfs】
HDOJ 1495 非常可乐 【bfs】
一共只有6种状态
a → b
a → c
b → a
b → c
c → a
c → b
bfs搜一遍即可
注意队列清空 标记数组清零
输入S为奇数时一定不符合要求，删除该情况剪枝
1 #include<iostream> 2 #include<algorithm> 3 #include<cstdio> 4 #include<cstring> 5 #include<queue> 6 using namespace std; 7 int S, N, M; 8 typedef struct state{ 9 int s, n, m; // 三个杯子的容量 10 int step; // 次数 11 }state; 12 queue<state> q; 13 bool vis[105][105][105]; 14 bool End(int a, int b, int c){ 15 if((a == b && c == 0) || (a == c && b == 0) || (b == c && a == 0)){ 16 return true; 17 } 18 else 19 return false; 20 } 21 22 int bfs(){ 23 memset(vis, 0, sizeof(vis)); 24 while(!q.empty()) q.pop(); 25 state start; 26 start.s = S, start.n = 0, start.m = 0, start.step = 0; 27 vis[S][0][0] = true; 28 //printf("start\n"); 29 q.push(start); 30 while(!q.empty()){ 31 state current, next; 32 int s, n, m, step; // current. 33 current = q.front(); 34 s = current.s, n = current.n, m = current.m, step = current.step; 35 //printf("%d\t%d\t%d\n", s, n, m); 36 37 if(End(s, n, m)){ // 判断结束 38 //printf("%d\n", step); 39 return step; 40 } 41 42 next.step = step+1; 43 if(s > 0){ // a → b / c 44 if(s > N-n){ // a → b a有剩余 45 next.s = s-(N-n); 46 next.n = N; 47 next.m = m; 48 if(vis[next.s][next.n][next.m] == false){ 49 vis[next.s][next.n][next.m] = true; 50 //printf("a → b a有剩余\n"); 51 q.push(next); 52 } 53 } 54 else{ // a → b a无剩余 55 next.s = 0; 56 next.n = n+s; 57 next.m = m; 58 if(vis[next.s][next.n][next.m] == false){ 59 vis[next.s][next.n][next.m] = true; 60 //printf("a → b a无剩余\n"); 61 q.push(next); 62 } 63 } 64 if(s > M-m){ // a → c a有剩余 65 next.s = s-(M-m); 66 next.n = n; 67 next.m = M; 68 if(vis[next.s][next.n][next.m] == false){ 69 vis[next.s][next.n][next.m] = true; 70 //printf("a → c a有剩余\n"); 71 q.push(next); 72 } 73 } 74 else{ // a → c a无剩余 75 next.s = 0; 76 next.n = n; 77 next.m = m+s; 78 if(vis[next.s][next.n][next.m] == false){ 79 vis[next.s][next.n][next.m] = true; 80 //printf("a → c a无剩余\n"); 81 q.push(next); 82 } 83 } 84 } 85 if(n > 0){ // b → a / c 86 if(n > S-s){ // b → a b有剩余 87 next.s = S; 88 next.n = n - (S-s); 89 next.m = m; 90 if(vis[next.s][next.n][next.m] == false){ 91 vis[next.s][next.n][next.m] = true; 92 //printf("b → a b有剩余\n"); 93 q.push(next); 94 } 95 } 96 else{ // b → a b无剩余 97 next.s = s+n; 98 next.n = 0; 99 next.m = m; 100 if(vis[next.s][next.n][next.m] == false){ 101 vis[next.s][next.n][next.m] = true; 102 //printf("b → a b无剩余\n"); 103 q.push(next); 104 } 105 } 106 if(n > M-m){ // b → c b有剩余 107 next.s = s; 108 next.n = n - (M-m); 109 next.m = M; 110 if(vis[next.s][next.n][next.m] == false){ 111 vis[next.s][next.n][next.m] = true; 112 //printf("b → c b有剩余\n"); 113 q.push(next); 114 } 115 } 116 else{ // b → c b无剩余 117 next.s = s; 118 next.n = 0; 119 next.m = m+n; 120 if(vis[next.s][next.n][next.m] == false){ 121 vis[next.s][next.n][next.m] = true; 122 //printf("b → c b无剩余\n"); 123 q.push(next); 124 } 125 } 126 } 127 if(m > 0){ // c → a / b 128 if(m > S-s){ // c → a c有剩余 129 next.s = S; 130 next.n = n; 131 next.m = m - (S-s); 132 if(vis[next.s][next.n][next.m] == false){ 133 vis[next.s][next.n][next.m] = true; 134 //printf("c → a c有剩余\n"); 135 q.push(next); 136 } 137 } 138 else{ // c → a c无剩余 139 next.s = s+m; 140 next.n = n; 141 next.m = 0; 142 if(vis[next.s][next.n][next.m] == false){ 143 vis[next.s][next.n][next.m] = true; 144 //printf("c → a c无剩余\n"); 145 q.push(next); 146 } 147 } 148 if(m > N-n){ // c → b c有剩余 149 next.s = s; 150 next.n = N; 151 next.m = m - (N-n); 152 if(vis[next.s][next.n][next.m] == false){ 153 vis[next.s][next.n][next.m] = true; 154 //printf("c → b c有剩余\n"); 155 q.push(next); 156 } 157 } 158 else{ // c → b c无剩余 159 next.s = s; 160 next.n = n+m; 161 next.m = 0; 162 if(vis[next.s][next.n][next.m] == false){ 163 vis[next.s][next.n][next.m] = true; 164 //printf("c → b c无剩余\n"); 165 q.push(next); 166 } 167 } 168 } 169 q.pop(); 170 } 171 return 0; 172 } 173 174 int main(){ 175 while(~scanf("%d%d%d", &S, &N, &M)){ 176 if(!S && !N && !M) break; 177 if(S & 1) printf("NO\n"); 178 else{ 179 int ans = bfs(); 180 if(!ans) printf("NO\n"); 181 else printf("%d\n", ans); 182 } 183 } 184 185 return 0; 186 }
