7.11__ 心灵终结

先对各种情况进行特判，可分为n==1 || m==1 ;  n==2 || m==2 ; n和m完全无规律四种情况进行讨论

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下面是程序

#include<iostream>#include<cstdio>#include<cstring>using namespace std;long long qz(long long x){if(x%8==2)return (x+2)/2;if(x%8==4)return (x+4)/2;if(x%8==6)return (x+2)/2;return x/2;}int main(){freopen("psycho.in","r",stdin);freopen("psycho.out","w",stdout);long long n,m,t;long long ans;cin>>t;for(int i=1;i<=t;i++){ans=0;scanf("%d%d",&n,&m);if(n==1){cout<<m<<endl;continue;}if(m==1){cout<<n<<endl;continue;}if(n==2 || m==2){ans=n*m;cout<<qz(ans)<<endl;continue;}ans=(n*m+1)/2;cout<<ans<<endl;}return 0;}