2016秋季练习

来源：lightOJ1183

线段树，稍加改动而已

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#define lson rt<<1
#define rson rt<<1|1
#define L (tree[rt].l)
#define R (tree[rt].r)
using namespace std;
const int  MAXN = 100010;
struct Segment{
    int l,r;
    long long sum;
    long long lazy;
}tree[MAXN<<2];
long long gcd(long long a,long long b){
    if(!b) return a;
    else return gcd(b,a%b);
}
inline void pushdown(int rt) {
    if(tree[rt].lazy!=-1) {
        long long lazy = tree[rt].lazy;
        int mid = (tree[rt].l + tree[rt].r)>>1;
        tree[rt].lazy = -1;
        tree[lson].lazy = tree[rson].lazy = lazy;
        tree[lson].sum = lazy * (tree[lson].r-tree[lson].l+1);
        tree[rson].sum = lazy * (tree[rson].r-tree[rson].l+1);
        tree[rt].sum = lazy * (tree[rt].r - tree[rt].l + 1);
    }
}
inline void pushup(int rt){
    tree[rt].sum = tree[lson].sum + tree[rson].sum;
}
void build(int rt,int l,int r){
    tree[rt].l = l;
    tree[rt].r = r;
    tree[rt].sum = 0;
    tree[rt].lazy = -1;
    if(l == r) return ;
    int mid = (l+r) >> 1;
    build(lson,l,mid);
    build(rson,mid+1,r);
    pushup(rt);
}
void update(int rt,int l,int r,int data){
    if(l <= tree[rt].l && tree[rt].r <= r) {
        tree[rt].lazy = data;
        tree[rt].sum = data*(tree[rt].r - tree[rt].l + 1);
        return ;
    }
    pushdown(rt);
    int mid = (tree[rt].l + tree[rt].r) >> 1;
    if(l <= mid) update(lson,l,r,data);
    if(r  > mid) update(rson,l,r,data);
    pushup(rt);
}
long long query(int rt,int l,int r){
    if(l <= tree[rt].l && tree[rt].r <= r){
        return tree[rt].sum;
    }
    pushdown(rt);
//    long long res = 0;
    int mid = (tree[rt].l + tree[rt].r) >> 1;
    if(r <= mid) return query(lson,l,r);
    else if(l > mid) return query(rson,l,r);
    else return (query(lson,l,mid) + query(rson,mid+1,r));
}
int main(){
    int T,nc = 1;
    scanf("%d",&T);
    while(T--){
        int n,Qm;
        scanf("%d%d",&n,&Qm);
        build(1,1,n);
        printf("Case %d:\n",nc++);
        while(Qm--){
            int op;
            scanf("%d",&op);
            if(op == 1) {
                int l,r,data;
                scanf("%d%d%d",&l,&r,&data);
                l++;r++;
                update(1,l,r,data);
            }
            else if(op == 2){
                int l,r;
                scanf("%d%d",&l,&r);
                l++;r++;
                long long sum = query(1,l,r);
                long long duan = (long long)r-l+1;
                long long du = gcd(sum,duan);
                sum /= du;
                duan /= du;
                if(duan == 1) printf("%lld\n",sum);
//                else if(sum == 0) printf("%lld\n",sum);
                else printf("%lld/%lld\n",sum,duan);
            }
        }
    }
    return 0;
}