luogu P4231 三步必杀 题解

Posted 2020-12-02 misakaazusa

题目链接：https://www.luogu.org/problemnew/show/P4231
诶 我很迷啊..这跟树状数组有什么关系啊...拿二阶差分数组过了..？

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#define ll long long
#define ri register
using namespace std;
const int maxn = 11000001;
ll diff[maxn], ddiff[maxn], bit[maxn], n, m, ans, maxx = -1;
inline int read()
{
    int k=0;
    char c;
    c=getchar();
    while(!isdigit(c))c=getchar();
    while(isdigit(c)){k=(k<<3)+(k<<1)+c-'0';c=getchar();}
    return k;
}
int main()
{
    //scanf("%lld%lld",&n,&m);
    n = read(); m = read();
    for(ri int i = 1; i <= m; i++)
    {
        ll l, r, s, e, d;
        //scanf("%lld%lld%lld%lld",&l,&r,&s,&e);
        l = read(); r = read(); s = read(); e = read();
        d = (e-s)/(r-l);
        ddiff[l] += s;
        ddiff[l+1] = ddiff[l+1] + d - s;
        ddiff[r+1] = ddiff[r+1] - d - e;
        ddiff[r+2] += e;
    }
    diff[1] = ddiff[1];
    for(ri int i = 2; i <= n; i++)
    {
        diff[i] = ddiff[i] + diff[i-1];
    }
    bit[1] = diff[1];
    ans = bit[1];
    for(ri int i = 2; i <= n; i++)
    {
        bit[i] = diff[i] + bit[i-1];
        ans = ans^bit[i];
        if(bit[i] > maxx)
        maxx = bit[i];
    }
    printf("%lld %lld",ans,maxx);
    return 0;
}