hdu 1166 敌兵布阵 (线段树、树状数组模板，单点更新）

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hdu 1166

方法1：线段树

#include <iostream>#include<algorithm>#include <cstdio>#include <cstring>using namespace std;const int MAXN = 55555;struct node{int l, r;int val;};int a[MAXN];node T[MAXN * 4 + 10];void build(int rt, int begin, int end) {if(begin == end) {T[rt].val = a[begin];T[rt].l = begin;T[rt].r = end;}else {int mid = (begin + end) >> 1;build(rt << 1, begin, mid);build(rt << 1 | 1, mid + 1, end);T[rt].val = T[rt << 1].val + T[rt << 1 | 1].val;T[rt].l = begin;T[rt].r = end;}}void updata(int rt, int id, int add) {if(T[rt].l == T[rt].r) {T[rt].val += add;}else {int mid = (T[rt].l + T[rt].r) >> 1;if(id <= mid) updata(rt << 1, id, add);else updata(rt << 1 | 1, id, add);T[rt].val = T[rt << 1].val + T[rt << 1 | 1].val;}}int query(int rt, int l, int r) {if(T[rt].l >= l && T[rt].r <= r) {return T[rt].val;}else {int mid = (T[rt].l + T[rt].r) >> 1;if(r <= mid) return query(rt << 1, l, r);else if(l > mid) return query(rt << 1 | 1, l, r);else return query(rt << 1, l, mid) + query(rt << 1 | 1, mid + 1, r);}}int main() {//freopen("input.txt", "r", stdin);int T;scanf("%d", &T);int N;int j;for(j = 1; j <= T; j++) {printf("Case %d:\n", j);scanf("%d", &N);int i;for(i = 1; i <= N; i++) {scanf("%d", a + i);}build(1, 1, N);    char str[10];    int x, y;    while(1) {    scanf("%s", str);    if(str[0] == 'E') break;    //此处注意runtime error     scanf("%d %d", &x, &y);    if(str[0] == 'Q') {    printf("%d\n", query(1, x, y));}else if(str[0] == 'A') {updata(1, x, y);}else {updata(1, x, -y);}}}    return 0;}

方法2：树状数组

#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>using namespace std;const int maxn = 50005;int sum[maxn], N;int lowbit(int x) {return x & (-x);}void update(int index, int val) {int i;for(i = index; i <= N; i += lowbit(i)) {sum[i] += val;}}int getsum(int index) {int i;int res = 0;for(i = index; i > 0; i -= lowbit(i)) {res += sum[i];}return res;}int main() {int T;int kase = 1;scanf("%d", &T);while(T--) {printf("Case %d:\n", kase++);scanf("%d", &N);memset(sum, 0, sizeof(sum));int i, tmp;for(i = 1; i <= N; i++) {scanf("%d", &tmp);update(i, tmp);}string str;int n, m;while (cin >> str) {      if (str == "End") break;     scanf("%d%d", &n, &m);      if (str == "Query")        printf("%d\n", getsum(m) - getsum(n - 1));      else if (str == "Add")        update(n, m);      else update(n, -m);    }}return 0;}

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