View difference between Paste ID: 534GY5a3 and 9kA0DTUX

 const int N = 1 << 20;
 
 struct seg_tree {
 	int t[N * 2 + 228];
 	int mod[N * 2 + 228];
 
 	seg_tree() {
 
 	}
 
 	void build(vector<int> a) {
 		fill(t, t + N * 2, INF);
 		for (int i = 0; i < a.size(); ++i) {
 			t[i + N] = a[i];
  		}
  		for (int i = N - 1; i >= 0; --i) {
  			t[i] = min(t[i * 2], t[i * 2 + 1]);
  		}
 	}
 
 	void chg(int i, int v) {
 		i += N;
 		t[i] = v;
 		while (i != 1) {
 			// t[i >> 1] = t[i] + t[i ^ 1];
 			i >>= 1;
 			t[i] = min(t[i * 2], t[i * 2 + 1]);
 		}
 	}
 
 	void push(int i, int len) {
 		if (mod[i] != -1) {
 			if (i < N) {
 				mod[i * 2] = mod[i];
 				mod[i * 2 + 1] = mod[i];
 			}
 			t[i] = mod[i];
 			mod[i] = -1;
 		}
 	}
 
 	int get(int i, int L, int R, int Ln, int Rn) {
 		push(i, R - L);
 		if (Ln <= L && R <= Rn) {
 			return t[i];
 		}
 		if (Rn <= L || R <= Ln) {
 			return INF;
 		}
 		int M = (L + R) >> 1;
 		return min(get(i * 2,     L, M, Ln, Rn),
 			   	   get(i * 2 + 1, M, R, Ln, Rn));
 	}
 
 	int find(int i, int L, int R, int Ln, int Rn, int val) {
 		push(i, R - L);
 		if (Rn <= L || R <= Ln || t[i] >= val) return -1;
 		if (R - L == 1) return L;
 		int M = (L + R) >> 1;
 		int ans = find(i * 2, L, M, Ln, Rn, val);
 		if (ans == -1) {
 			ans = find(i * 2 + 1, M, R, Ln, Rn, val);
 		}
 		return ans;
 	}
 
 	void chg(int i, int L, int R, int Ln, int Rn, int d) {
 		if (Ln <= L && R <= Rn) {
 			mod[i] = d;
 			push(i, R - L);
 			return;
 		}
 		push(i, R - L);
 		if (Rn <= L || R <= Ln) {
 			return;
 		}
 		int M = (L + R) >> 1;
 		chg(i * 2    , L, M, Ln, Rn, d);
 		chg(i * 2 + 1, M, R, Ln, Rn, d);
 		t[i] = min(t[i * 2], t[i * 2 + 1]);
 	}
 };