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;
}