Introduction to line tree

# Include <iostream> # include <cmath> # include <cstring> # include <algorithm> using namespace STD; int n, m; int A [100001]; // Number of leaf knots N _ int64 ans; struct {int L, R; _ int64 sum, add; // _ int64} tree [400000]; // In the number, the number of all nodes is about 2 ^ 2 * n layers. logn H = logn + 1 or + 2. Each insert update cannot exceed O (logn) void build (INT l, int R, int I) {tree [I]. L = L; tree [I]. R = r; tree [I]. add = 0; If (L = r) {tree [I]. sum = A [l]; // The value of the leaf node = return of the input array;} int mid = (L + r)/2; build (L, mid, 2 * I); Build (Mid + 1, R, 2 * I + 1); tree [I]. sum = tree [2 * I]. sum + tree [2 * I + 1]. SUM;} void updata (int l, int R, int add, int I) {If (tree [I]. l> r | tree [I]. r <L) return; If (tree [I]. l> = L & tree [I]. r <= r) {tree [I]. sum + = (tree [I]. r-tree [I]. L + 1) * Add; tree [I]. add + = add; return; // lazy is only added to break down a unique subinterval} If (tree [I]. add) // lazy edge update edge maintenance in order to ensure that the child's ADD and sum are correct, the meaning of the current add = 0 (updated to the bottom) after the update {tree [2 * I]. sum + = (tree [2 * I]. r-tree [2 * I]. L + 1) * tree [I]. add; tree [2 * I]. add + = tree [I]. add; tree [2 * I + 1]. sum + = (tree [2 * I + 1]. r-tree [2 * I + 1]. L + 1) * tree [I]. add; tree [2 * I + 1]. add + = tree [I]. add; tree [I]. add = 0;} updata (L, R, add, 2 * I); updata (L, R, add, 2 * I + 1); tree [I]. sum = tree [2 * I]. sum + tree [2 * I + 1]. SUM;} void query (int l, int R, int I) {If (tree [I]. l> r | tree [I]. r <L) return; If (tree [I]. l> = L & tree [I]. r <= r) {Ans + = tree [I]. SUM; return;} If (tree [I]. add) // lazy side query side maintenance {tree [2 * I]. sum + = (tree [2 * I]. r-tree [2 * I]. L + 1) * tree [I]. add; tree [2 * I]. add + = tree [I]. add; tree [2 * I + 1]. sum + = (tree [2 * I + 1]. r-tree [2 * I + 1]. L + 1) * tree [I]. add; tree [2 * I + 1]. add + = tree [I]. add; tree [I]. add = 0;} query (L, R, 2 * I); query (L, R, 2 * I + 1); tree [I]. sum = tree [2 * I]. sum + tree [2 * I + 1]. SUM;} int main () {// freopen ("in.txt", "r", stdin); int I, X, Y, Z; char C; while (scanf ("% d", & N, & M )! = EOF) {for (I = 1; I <= N; I ++) scanf ("% d", & A [I]); Build (1, n, 1); scanf ("% * C"); for (I = 1; I <= m; I ++) {scanf ("% C", & C ); if (C = 'q') {scanf ("% d % * C", & X, & Y); ans = 0; query (x, y, 1); printf ("% i64d \ n", ANS);} else {scanf ("% d % * C", & X, & Y, & Z); updata (X, Y, Z, 1) ;}} return 0 ;}

Analyzed the code annotation of the first-line segment tree