洛谷线段树题目代码

参考链接线段树从入门到进阶
以下是我在洛谷中对应题目的AC代码

1. 【修改区间，查找单值】
   3368 树状数组2

#include
#include
#include
using namespace std;
struct Node {
     
    int sum;
    int l,r;
}; 
void build_tree(int i, int l, int r, vector<Node>& node, vector<int>& arr) {
     
    node[i].l = l;
    node[i].r = r;
    if (l == r) {
     
        node[i].sum = arr[l];
        return;
    }
    int mid = (l + r) >> 1;
    build_tree(2 * i, l, mid, node, arr);
    build_tree(2 * i + 1, mid + 1, r, node, arr);
}
void modify_region(int i, int l, int r, int add, vector<Node>& node) {
     
	if (node[i].l >= l && node[i].r <= r) {
     
		node[i].sum += add;
		return;
	}
	if (node[2*i].r >= l) modify_region(2*i, l, r, add, node);
	if (node[2*i+1].l <= r) modify_region(2*i+1, l, r, add, node);
}
int get_single_num(int i, int index, vector<Node>& node) {
     
	int sum = node[i].sum;
	if (node[i].l == node[i].r) return sum;
	if (node[2*i].r >= index) sum += get_single_num(2*i, index, node);
	else sum += get_single_num(2*i+1, index, node);
	return sum; 
}
int main() {
     
    int n,m;
    scanf("%d %d", &n, &m);
    vector<int> arr(n+1);
    for (int i = 1; i <= n; ++i) {
     
        scanf("%d", &arr[i]);
    }
    vector<Node> node(4*n+2);
    //build tree
    build_tree(1, 1, n, node, arr);
    int op, left, right, add, index;
    for (int i = 0; i < m; ++i) {
     
    	scanf("%d", &op);
        if (op == 1) {
     
        	scanf("%d %d %d", &left, &right, &add);
            modify_region(1, left, right, add, node);
        }
        else {
     
            scanf("%d", &index);
            printf("%d\n", get_single_num(1, index, node));
        }
        
    }
    return 0;
}

2. 【修改单值，查找区间】
   3374 树状数组1

#include
#include
#include
using namespace std;
struct Node {
     
    int sum;
    int l,r;
}; 
void build_tree(int i, int l, int r, vector<Node>& node, vector<int>& arr) {
     
    node[i].l = l;
    node[i].r = r;
    if (l == r) {
     
    	//cout << "node " << i << ' ' << arr[l] << endl;
        node[i].sum = arr[l];
        return;
    }
    int mid = (l + r) >> 1;
    build_tree(2 * i, l, mid, node, arr);
    build_tree(2 * i + 1, mid + 1, r, node, arr);
    node[i].sum = node[2*i].sum + node[2*i+1].sum;
}
void modify_single_point(int i, int index, int add, vector<Node>& node) {
     
	node[i].sum += add;
    if (node[i].l == node[i].r) {
     
        return;
    }
    if (node[2*i].r >= index) modify_single_point(2*i, index, add, node);
    else modify_single_point(2*i+1, index, add, node);
    
}
int get_sum(int i, int l, int r, vector<Node>& node) {
     
    if (node[i].l >= l && node[i].r <= r) return node[i].sum;
    if (node[i].l > r || node[i].r < l) return 0;
    int sum = 0;
    if (node[2*i].r >= l) sum += get_sum(2*i, l, r, node);
    if (node[2*i+1].l <= r) sum += get_sum(2*i+1, l, r, node);
    return sum;
}
int main() {
     
    int n,m;
    scanf("%d %d", &n, &m);
    vector<int> arr(n+1);
    for (int i = 1; i <= n; ++i) {
     
        scanf("%d", &arr[i]);
    }
    vector<Node> node(4*n+2);
    //build tree
    build_tree(1, 1, n, node, arr);
    int op, index, add;
    for (int i = 0; i < m; ++i) {
     
    	scanf("%d %d %d", &op, &index, &add);
        if (op == 1) {
     
            modify_single_point(1, index, add, node);
        }
        else {
     
            //sum
            printf("%d\n", get_sum(1, index, add,node));
        }
    }
    return 0;
}