OJ-Problems-Source/CodeVS/1001_冰封.cpp

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2016-07-06 14:28:18 +08:00
#include <stdio.h>
const int BIG = 0x3f3f3f3f;
const int size = 501;
int N, min = BIG, max = -BIG, to;
int a[size][size];
bool used[size];
int save[size][2];
int save_cnt;
void dfs(int c);
int get();
void test();
int main(int argc, char* argv[]){
auto int M;
auto int x, y, v;
auto int fr;
// test();
scanf("%i%i", &N, &M);
for(auto int i = 0; i < M; i++){
scanf("%i%i%i", &x, &y, &v);
a[x][y] = v;
}
scanf("%i%i", &fr, &to);
used[fr] = true;
dfs(fr);
if(!save_cnt)
printf("IMPOSSIBLE");
else {
int cur = 0;
for(auto int i = 0; i < save_cnt; i++){
int q = save[i][1] / save[i][0];
if(q < save[cur][1] / save[cur][0])
cur = q;
// printf("save[%i][1] = %i, save[%i][0] = %i\n",i , save[i][1],i , save[i][0]);
}
max = save[cur][1];
min = save[cur][0];
get();
if(min == 1)
printf("%i", max);
else
printf("%i/%i", max, min);
}
return 0;
}
void dfs(int c) {
if(c == to) {
// printf("arrived.\n");
save[save_cnt][0] = min;
save[save_cnt][1] = max;
save_cnt++;
min = -BIG;
max = BIG;
return ;
}
for(auto int i = 0; i <= N; i++) {
if(a[c][i] && !used[i]) {
if(a[c][i] > max) max = a[c][i];
if(a[c][i] < min) min = a[c][i];
used[i] = true;
// printf("from %i to %i\n", c, i);
dfs(i);
used[i] = false;
}
}
}
int get(){
for(auto int i = 2; i <= max; i++){
if(min % i == 0 && max % i == 0){
min /= i;
max /= i;
i--;
}
}
}
void test(){
max = 6;
min = 3;
get();
printf("6 / 3 => %i / %i\n", max, min);
}