藍橋杯 操作格子 線段樹
阿新 • • 發佈:2018-12-21
對於20%的資料n <= 100,m <= 200。
對於50%的資料n <= 5000,m <= 5000。
對於100%的資料1 <= n <= 100000,m <= 100000,0 <= 格子權值 <= 10000。
簡單的線段樹區間更新
#include <stdio.h>#include <string.h>#include <algorithm>using namespace std;#define lson 2*i#define rson 2*i+1#define lc l,mid,2*i#define rc mid+1,r,2*i+1int sum,n,maxn;struct node{ int l,r,n,sum;} a[1000000];void init(int l,int r,int i){ a[i].l = l; a[i].r = r; a[i].n = 0; a[i].sum = 0; if(l!=r) { int mid = (l+r)/2; init(lc); init(rc); }}void insert(int i,int x,int m){ if(x>=a[i].l && x<=a[i].r) { a[i].n=m; a[i].sum=m; } if (a[i].l == a[i].r) return ; int mid = (a[i].l+a[i].r)/2; if(x>mid) insert(2*i+1,x,m); else insert(2*i,x,m); a[i].sum = a[2*i].sum+a[2*i+1].sum; a[i].n = max(a[2*i].n,a[2*i+1].n);}int find_max(int x,int y,int i){ if(x == a[i].l && y == a[i].r) return a[i].n; int mid = (a[i].l+a[i].r)/2; if(x>mid) return find_max(x,y,2*i+1); else if(y<=mid) return find_max(x,y,2*i); else return max(find_max(x,mid,2*i),find_max(mid+1,y,2*i+1));}int find_sum(int x,int y,int i){ if(a[i].l == x && a[i].r == y) return a[i].sum; int mid = (a[i].l+a[i].r)/2; if(x>mid) return find_sum(x,y,2*i+1); else if(y<=mid) return find_sum(x,y,2*i); else return find_sum(x,mid,2*i)+find_sum(mid+1,y,2*i+1);}int main(){ int n,m,i,j,b,x,y,cas; scanf("%d%d",&n,&m); init(1,n,1); for(i = 1; i<=n; i++) { scanf("%d",&b); insert(1,i,b); } while(m--) { scanf("%d%d%d",&cas,&x,&y); if(cas==1) insert(1,x,y); else if(cas==2) printf("%d\n",find_sum(x,y,1)); else if(cas==3) printf("%d\n",find_max(x,y,1)); } return 0;}