前缀和与差分 AcWing 797. 差分

曾经终败给现在 2023-09-28 11:15 83阅读 0赞

## 前缀和与差分 AcWing 797. 差分 ##

### 原题链接 ###

[AcWing 797. 差分][AcWing 797.]

### 算法标签 ###

差分

### 思路 ###

![在这里插入图片描述][febfeec9d69d442e9d703269c67f0e15.png]  
[转自该题解][Link 1]

### 代码 ###

#include<bits/stdc++.h>
    #define int long long
    #define rep(i, a, b) for(int i=a;i<b;++i)
    #define Rep(i, a, b) for(int i=a;i>b;--i)
    using namespace std;
    const int N = 100005;
    int a[N], b[N];
    inline int read(){
       int s=0,w=1;
       char ch=getchar();
       while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}
       while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();
       return s*w;
    }
    void put(int x) {
        if(x<0) putchar('-'),x=-x;
        if(x>=10) put(x/10);
        putchar(x%10^48);
    }
    signed main(){
    	ios::sync_with_stdio(false);
    	cin.tie(0);
    	cout.tie(0);
    	int n=read(), m=read();
    	rep(i, 1, n+1){
    	   a[i]=read();
    	   b[i]+=a[i];
    	   b[i+1]-=a[i];
    	}
    	while(m--){
    	    int l=read(), r=read(), c=read();
    	    b[l]+=c;
    	    b[r+1]-=c;
    	}
    	rep(i, 1, n+1){
    	    b[i]+=b[i-1];
    	}
    	rep(i, 1, n+1){
    	    printf("%lld ", b[i]);
    	}
    	return 0;
    }

### y总代码 ###

#include <iostream>
    
    using namespace std;
    
    const int N = 100010;
    
    int n, m;
    int a[N], b[N];
    
    void insert(int l, int r, int c)
    {
        b[l] += c;
        b[r + 1] -= c;
    }
    
    int main()
    {
        scanf("%d%d", &n, &m);
        for (int i = 1; i <= n; i ++ ) scanf("%d", &a[i]);
    
        for (int i = 1; i <= n; i ++ ) insert(i, i, a[i]);
    
        while (m -- )
        {
            int l, r, c;
            scanf("%d%d%d", &l, &r, &c);
            insert(l, r, c);
        }
    
        for (int i = 1; i <= n; i ++ ) b[i] += b[i - 1];
    
        for (int i = 1; i <= n; i ++ ) printf("%d ", b[i]);
    
        return 0;
    }

### 总结学习 ###

由于插入操作前后重复运用 ，可以封装为函数。

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![在这里插入图片描述][9cb4cb80a18345158f8a69e2f196e5b9.png]

[AcWing 797.]: https://www.acwing.com/problem/content/799/
[febfeec9d69d442e9d703269c67f0e15.png]: https://img-blog.csdnimg.cn/febfeec9d69d442e9d703269c67f0e15.png
[Link 1]: https://www.acwing.com/solution/content/26588/
[9cb4cb80a18345158f8a69e2f196e5b9.png]: https://img-blog.csdnimg.cn/9cb4cb80a18345158f8a69e2f196e5b9.png