5.10号个人赛补题

A题

没看懂，数学水平达不到……

最后是x可以被gcd（a，b）除后为偶数

#include<algothrim>
#include<iostream>

using namespace std;
int gcd(int x,int y)
{
    if(x%y==0)
        return y;
    return gcd(y,x%y);
}

int main(){
    int T;
    cin>>T;
    while(T--){
         int a,b,n;
         cin>>n>>a>>b;
         int MOD=gcd(a,b);
         if(n/MOD%2==0)
             cout<<"NO"<<endl;
         else 
              cout<<"yes"<<endl;
   
     }

}
          

 F：差分

后来做了一个比较相似的题目

http://acm.hdu.edu.cn/showproblem.php?pid=1556

#include<iostream>
#include<cstdio>
#include<set>
#include<queue>
#include<stack>
#include<vector>
#include<bitset>
#include<cstring>
#include<string>
#include<algorithm>
using namespace std;
typedef long long ll;
const int MAXN=1e5+10;
inline int read(){
    int x=0,y=1;
    char ch=getchar();
    while(ch<'0'||ch>'9'){
        if(ch=='-'){
            y=-1;
        }
        ch=getchar();
    }
    while(ch>='0'&&ch<='9'){
        x=(x<<1)+(x<<3)+(ch^48);
        ch=getchar();
    }
    return x*y;
}
int main(){
    int n; 
    while(scanf("%d",&n)){
        int a[MAXN];
        memset(a,0,sizeof(a));
        if(n==0)
            break;
        int l,r;
        for(int i =1;i<=n;i++){
            scanf("%d%d",&l,&r);
            a[l]++;a[r+1]--;
        }
        for(int i =1;i<=n;i++){
            a[i]+=a[i-1];
        }    
        for(int i =1;i<=n;i++){
            if(i!=1)
                printf(" ");
            printf("%d",a[i]);
        }    
        printf("\n");
    }
    

    return 0;
}