POJ3468 A Simple Problem with Integers
解题思路:线段树区间更新模板题,注意比较与点更新的区别。不解释,上代码:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
1 #include<cstdio> 2 using namespace std; 3 #define lson l, m, rt << 1 4 #define rson m+1, r, rt << 1 | 1 5 #define LL long long 6 #define maxn 100005 7 LL sum[maxn<<2], add[maxn<<2]; 8 9 void PushUp(int rt) 10 { 11 sum[rt] = sum[rt<<1] + sum[rt<<1 | 1]; 12 } 13 14 void PushDown(int rt, int m) 15 { 16 if(add[rt]) 17 { 18 add[rt<<1] += add[rt]; 19 add[rt<<1|1] += add[rt]; 20 sum[rt<<1] += (m - (m>>1)) * add[rt]; 21 sum[rt<<1|1] += (m >> 1) * add[rt]; 22 add[rt] = 0; 23 } 24 return ; 25 } 26 27 void Build(int l, int r, int rt) 28 { 29 add[rt] = 0; 30 if(l == r) 31 { 32 scanf("%I64d", &sum[rt]); 33 return ; 34 } 35 int m = (l + r) >> 1; 36 Build(lson); 37 Build(rson); 38 PushUp(rt); 39 } 40 41 LL Query(int L, int R, int l, int r, int rt) 42 { 43 if(L <= l && R >= r) return sum[rt]; 44 PushDown(rt, r-l+1); 45 int m = (l + r) >> 1; 46 LL ret = 0; 47 if(L <= m) ret += Query(L, R, lson); 48 if(R > m) ret += Query(L, R, rson); 49 return ret; 50 } 51 52 void Update(int L, int R, int c, int l, int r, int rt) 53 { 54 if(L <= l && R >= r) 55 { 56 add[rt] += c; 57 sum[rt] += (LL)c * (r - l + 1); 58 return ; 59 } 60 PushDown(rt, r - l + 1); 61 int m = (l + r) >> 1; 62 if(L <= m) Update(L, R, c, lson); 63 if(R > m) Update(L, R, c, rson); 64 PushUp(rt); 65 } 66 67 int main() 68 { 69 int n, m, a, b, c; 70 char str[5]; 71 scanf("%d %d", &n, &m); 72 Build(1, n, 1); 73 while(m--) 74 { 75 scanf("%s", str); 76 if(str[0] == 'Q') 77 { 78 scanf("%d %d", &a, &b); 79 LL ans = Query(a, b, 1, n, 1); 80 printf("%I64d\n", ans); 81 } 82 else 83 { 84 scanf("%d %d %d", &a, &b, &c); 85 Update(a, b, c, 1, n, 1); 86 } 87 } 88 return 0; 89 }