POJ_3468 A Simple Problem with Integers 【线段树区间查询+修改】

一、题目

POJ3468

二、分析

裸的线段树区间查询+修改。

三、AC代码

 #include <cstdio>
 #include <iostream>
 #include <algorithm>

 using namespace std;

 #define ll long long
 #define lson l, mid, rt << 1
 #define rson mid + 1, r, rt << 1 | 1
 const int MAXN = 1e5 + ;
 ll add[MAXN << ], sum[MAXN << ];

 void PushUp(int rt)
 {
     sum[rt] = sum[rt << ] + sum[rt <<  | ];
     return;
 }

 void PushDown(int ln, int rn, int rt)
 {
     if(add[rt])
     {
         sum[rt << ] += (ll) ln * add[rt];
         sum[rt <<  | ] += (ll) rn * add[rt];
         add[rt << ] += add[rt];
         add[rt <<  | ] += add[rt];
         add[rt] = ;
     }
     return;
 }

 void Build(int l, int r, int rt)
 {
     add[rt] = ;
     if(l == r)
     {
         scanf("%lld", &sum[rt]);
         return;
     }
     int mid = (l + r) >> ;
     Build(lson);
     Build(rson);
     PushUp(rt);
     return;
 }

 void Update(int L, int R, int c, int l, int r, int rt)
 {
     if(L <= l && r <= R)
     {
         add[rt] += c;
         sum[rt] += (ll)(r - l + ) * c;
         return;
     }
     int mid = (l + r) >> ;
     PushDown(mid - l + , r - mid, rt);
     if(L <= mid)
     {
         Update(L, R, c, lson);
     }
     if(R > mid)
     {
         Update(L, R, c, rson);
     }
     PushUp(rt);
     return;
 }

 ll Query(int L, int R, int l, int r, int rt)
 {
     if(L <= l && r <= R)
         return sum[rt];
     int mid = (l + r) >> ;
     PushDown(mid - l + , r - mid, rt);
     ll ans = ;
     if(L <= mid)
     {
         ans += Query(L, R, lson);
     }
     if(R > mid)
     {
         ans += Query(L, R, rson);
     }
     return ans;
 }

 int main()
 {
     //freopen("input.txt", "r", stdin);
     int N, Q;
     scanf("%d %d", &N, &Q);
     Build(, N, );
     char s[];
     for(int i = ; i < Q; i++)
     {
         int L, R, C;
         scanf("%s", s);
         if(s[] == 'Q')
         {
             scanf("%d %d", &L, &R);
             printf("%I64d\n", Query(L, R, , N, ));
         }
         else
         {
             scanf("%d %d %d", &L, &R, &C);
             Update(L, R, C, , N, );
         }
     }
 }