HDU1166单点更新

敌兵布阵 HDU - 1166

多组输入，注意清除tr数组

维护一个前缀数组，耗时有点大

#include <cstdio>
#include <cstring>
using namespace std;
const int maxn = 5e4 + 5;
int t, n;
int sum[maxn], num[maxn];
char str[10];
int main() {
    // freopen("in.txt", "r", stdin);
    scanf("%d", &t);
    for (int kase = 1; kase <= t; kase++) {
        memset(sum, 0, sizeof(sum));
        scanf("%d", &n);
        for (int i = 1; i <= n; i++) {
            scanf("%d", num + i);
            sum[i] = sum[i - 1] + num[i];
        }
        int a, b;
        printf("Case %d:\n", kase);
        while (scanf("%s", str) && str[0] != 'E') {
            scanf("%d%d", &a, &b);
            if (str[0] == 'Q') {
                int res = sum[b] - sum[a - 1];
                printf("%d\n", res);
                continue;
            }
            else if (str[0] == 'A') {
                for (int i = a; i <= n; i++) {
                    sum[i] += b;
                }
            }
            else if (str[0] == 'S') {
                for (int i = a; i <= n; i++) {
                    sum[i] -= b;
                }
            }
        }
    }
    return 0;
}

树状数组模板

#include<bits/stdc++.h>
using namespace std;
#define sc(n) scanf("%c",&n)
#define sd(n) scanf("%d",&n)
#define pd(n) printf("%d\n", (n))
#define sdd(n,m) scanf("%d %d",&n,&m)
#define sddd(n,m,z) scanf("%d %d %d",&n,&m,&z)
#define pdd(n,m) printf("%d %d\n",n, m)
#define ms(a,b) memset(a,b,sizeof(a))
#define mod(x) ((x)%MOD)
#define lowbit(x) (x & (-x))

typedef long long ll;
typedef pair<int, int> PII;
typedef vector<int> VI;
typedef vector<string> VS;
const int MOD = 10000007;
const int inf = 0x3f3f3f3f;
const int maxn = 5e5 + 100;
int n, tr[maxn], t;

void update(int x, int val) {
	while (x <= n) {
		tr[x] += val;
		x += lowbit(x);
	}
}

int getsum(int x) {
	int res = 0;
	while (x) {
		res += tr[x];
		x -= lowbit(x);
	}
	return res;
}

int main() {
	//freopen("in.txt", "r", stdin);
	//ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	int N; cin >> N;
	for (int K = 1; K <= N; ++K) {
		ms(tr, 0);
		cin >> n;
		for (int i = 1; i <= n; ++i)cin >> t, update(i, t);
		printf("Case %d:\n", K);
		string s; int a, b;
		while (cin >> s && s != "End") {
			cin >> a >> b;
			if (s == "Query")cout << getsum(b) - getsum(a - 1) << endl;
			if (s == "Add") update(a, b);
			if (s == "Sub") update(a, -b);
		}
	}

	return 0;
}

线段树

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;

typedef long long LL;
typedef pair<int, int> pii;

const int maxn = 2e5 + 5;
const int INF = 0x3f3f3f3f;

int sum[maxn * 4], A[maxn];

void PushUp(int rt) {
    sum[rt] = sum[rt * 2] + sum[rt * 2 + 1];
}
void Build(int l, int r, int rt) {
    if (l == r) {
        sum[rt] = A[l];
        return;
    }
    int m = (l + r) / 2;
    Build(l, m, rt * 2);
    Build(m + 1, r, rt * 2 + 1);
    PushUp(rt);
}
void Update(int L, int c, int l, int r, int rt) {
    if (r == l) {
        sum[rt] += c;
        return;
    }
    int m = (l + r) / 2;
    if (L <= m) Update(L, c, l, m, rt * 2);
    else Update(L, c, m + 1, r, rt * 2 + 1);
    PushUp(rt);
}
int Query(int L, int R, int l, int r, int rt) {
    if (L <= l && r <= R) {
        return sum[rt];
    }
    int m = (l + r) / 2;
    int ans = 0;
    if (L <= m) ans += Query(L, R, l, m, rt * 2);
    if (R > m) ans += Query(L, R, m + 1, r, rt * 2 + 1);
    return ans;
}

int main() {
    // freopen("in.txt", "r", stdin);
    char c;
    int T;
    int n, m, a, b;
    char str[10];
    scanf("%d", &T);
    for (int kase = 1; kase <= T; kase++) {
        printf("Case %d:\n", kase);
        scanf("%d", &n);
        memset(sum, 0, sizeof(sum));
        memset(A, 0, sizeof(A));
        for (int i = 1; i <= n; i++) scanf("%d", A + i);
        Build(1, n, 1);
        while (scanf("%s", str) && str[0] != 'E') {
            scanf("%d%d", &a, &b);
            if (str[0] == 'Q') {
                printf("%d\n", Query(a, b, 1, n, 1));
            }
            else if (str[0] == 'A') {
                Update(a, b, 1, n, 1);
            }
            else if (str[0] == 'S') {
                Update(a, -b, 1, n, 1);
            }
        }
    }
    return 0;
}