LOJ 6279 数列分块入门3 分块基础

思路：分块+二分

这道题也调试了很长时间，还有莫名RE，可是明明数组已经开够了啊，还是要再开大一点。

 

记录下代码：

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cmath>
using namespace std;
const int maxn = 100010;
const int maxm = 330;

struct u {
    int v,i;
    bool operator < (const u &rhs) const {
      return v < rhs.v;
    }
}B[maxn+maxm];

int n, N, S;
int A[maxn], ID[maxn], addv[maxm], ind[maxn];

void update(int x,int k) {
    while(B[x].v > B[x+1].v && x != ID[k]*S) {
      ind[B[x].i] = x+1;
      ind[B[x+1].i] = x;
        swap(B[x],B[x+1]);
        x++;
    }

    while(B[x].v < B[x-1].v && x != (ID[k]-1)*S+1) {
        ind[B[x].i] = x-1;
        ind[B[x-1].i] = x;
        swap(B[x],B[x-1]);
        x--;
    }
}

void add(int x,int y,int c) {
    if(ID[x] + 1 >= ID[y]) {
        for(int i = x;i <= y;i++) {
            A[i] += c;
            B[ind[i]].v -= c;
            update(ind[i],i);
        }
        return;
    }
    
    int l = ID[x]+1, r = ID[y]-1;
    for(int i = l;i <= r;i++) addv[i] += c;
    
    for(int i = x;i <= y;) {
        A[i] += c;
        B[ind[i]].v -= c;
        update(ind[i],i);
        if(i == (l-1)*S) i = r*S + 1;
        else i++;
    }
    return;
}

int query(int x,int y,int c) {
    int ret = -(1<<30);
    if(ID[x] + 1 >= ID[y]) {
        for(int i = x;i <= y;i++) {
        if(A[i] + addv[ID[i]] >= c) continue;
            ret = max(ret, A[i] + addv[ID[i]]);
        }
        if(ret == -(1<<30)) return -1;
        else return ret;
    }

    int l = ID[x] + 1, r = ID[y] - 1;
    for(int i = l;i <= r;i++) {
        int ed = i*S;
        int be = (i-1)*S + 1;
        if(-B[ed].v + addv[i] < c) {
            u tp = *upper_bound(B+be,B+be+S,(u){-(c-addv[i]),0});
            ret = max(ret, -tp.v + addv[i]);
        }
    }

    for(int i = x;i <= y;) {
        if(A[i] + addv[ID[i]] >= c) {
            if(i == (l-1)*S) i = r*S + 1;
            else i++;
            continue;
        }
        ret = max(ret, A[i] + addv[ID[i]]);
        if(i == (l-1)*S) i = r*S + 1;
        else i++;
    }
    if(ret == -(1<<30)) return -1;
    else return ret;
}

int main() {
    scanf("%d",&n);
    
    S = sqrt(n);
    N = (n-1)/S + 1;
    for(int i = 1;i <= n;i++) {
        scanf("%d",&A[i]);
        B[i].v = -A[i];
        B[i].i = i;
        ID[i] = (i-1)/S + 1;
    }
    
    for(int i = 1;i <= N;i++) {
        int be = (i-1)*S + 1;
        cout<<be<<endl;
        sort(B+be,B+be+S);
    }

    for(int i = 1;i <= n;i++) {
        ind[B[i].i] = i;
    }
    
    int opt,l,r,c;
    
  for(int i = 1;i <= n;i++) {
      scanf("%d %d %d %d",&opt,&l,&r,&c);
      if(!opt) add(l,r,c);
      else printf("%d\n", query(l,r,c));
    }
    return 0;
}