1021. Couples

TAG 括号匹配

偶然发现一道自己之前没ac的题，而且都是CE。

刚好现在弄清楚了，大数组要放到main函数外。不然会有奇怪的错误。跟编译时数据的分配位置有关。

i686-linux-4.4.........crt1.o: In function `_start':
(.text+0x18): undefined reference to `main'
collect2: ld returned 1 exit status

赶紧改一改然后ac。当作括号匹配做。。

// source code of submission 297499, Zhongshan University Online Judge System #include<cstdio> #include<memory> #include<stack> using namespace std; int couple[200005]; int main() { int n; while (scanf("%d", &n), n!=0) { int x,y; stack<int> match; bool ok=true; int k=0; for (int i=0; i<n; ++i) { scanf("%d%d",&x, &y); if (ok) { ok= ( (x-y)%2+2 )%2==1; } couple[ x-1 ]=k; couple[ y-1 ]=k; ++k; } if ( !ok ) { printf("No/n"); continue; } match.push( couple[0] ); for (int i=1; i<2*n; ++i) { if( match.empty() || couple[i]!=match.top() ) { match.push(couple[i]); } else { match.pop(); } } if ( match.empty() ) { printf("Yes/n"); } else { printf("No/n"); } } return 0; }