#include<bits/stdc++.h> using namespace std; int main(){ int n,m; cin>>n>>m; cout<<n*m/2; return 0; }

他没判断i+1和j+1有没有超出界限 然后我帮忙省了一大堆代码

#include<iostream> #include<iostream> #include<iostream> #include<iostream> #include<iostream> #include<iostream> #include<iostream> #include<iostream> using namespace std; int main(){ int a,b; cin>>a>>b; cout<<a*b/2; return 0; }