RMQ不能实现更新。
#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; typedef long long LL; const int MAXN = 100100; const int MOD7 = 1e9 + 7; const int MOD9 = 1e9 + 9; const int INF = 2e9; const double EPS = 1e-6; const double PI = 3.14159265358979; const int dir_4r[] = { -1, 1, 0, 0 }; const int dir_4c[] = { 0, 0, -1, 1 }; const int dir_8r[] = { -1, -1, -1, 0, 0, 1, 1, 1 }; const int dir_8c[] = { -1, 0, 1, -1, 1, -1, 0, 1 }; int input[MAXN]; int dp[MAXN][20]; int GCD(int a, int b) { int r; while (b) { r = a % b; a = b; b = r; } return a; } //RMQ初始化 void init(int n) { for (int i = 0; i < n; ++i) dp[i][0] = input[i]; for (int j = 1; (1 << j) <= n; ++j) for (int i = 0; i + (1 << j) - 1 < n; ++i) dp[i][j] = GCD(dp[i][j - 1], dp[i + (1 << (j - 1))][j - 1]); } int getGcd(int l, int r) { int k = 0; while ((1 << (k + 1)) <= r - l + 1) k++; return GCD(dp[l][k], dp[r - (1 << k) + 1][k]); } int main() { //system("pause"); return 0; }
线段树能够实现更新
#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; typedef long long LL; const int MAXN = 500500; const int MOD7 = 1e9 + 7; const int MOD9 = 1e9 + 9; const int INF = 2e9; const double EPS = 1e-6; const double PI = 3.14159265358979; const int dir_4r[] = { -1, 1, 0, 0 }; const int dir_4c[] = { 0, 0, -1, 1 }; const int dir_8r[] = { -1, -1, -1, 0, 0, 1, 1, 1 }; const int dir_8c[] = { -1, 0, 1, -1, 1, -1, 0, 1 }; #define lson (rt*2+1) #define rson (rt*2+2) struct Node { int l, r; int val; int mid() { return (l + r) >> 1; } }; Node tree[MAXN << 2]; int input[MAXN]; int GCD(int a, int b) { int r; while (b) { r = a%b; a = b; b = r; } return a; } void buildTree(int rt, int l, int r) { tree[rt].l = l; tree[rt].r = r; if (l == r) tree[rt].val = input[l]; else { int mid = tree[rt].mid(); buildTree(lson, l, mid); buildTree(rson, mid + 1, r); tree[rt].val = GCD(tree[lson].val, tree[rson].val); } } //单点更新 void update(int rt, int pos, int val) { if (tree[rt].l == tree[rt].r) { tree[rt].val = val; return; } int mid = tree[rt].mid(); if (pos <= mid) update(lson, pos, val); else update(rson, pos, val); tree[rt].val = GCD(tree[lson].val, tree[rson].val); } int query(int rt, int l, int r) { if (tree[rt].l == l && tree[rt].r == r) return tree[rt].val; int mid = tree[rt].mid(); if (mid >= r) return query(lson, l, r); else if (mid < l) return query(rson, l, r); else { int q1 = query(lson, l, mid); int q2 = query(rson, mid + 1, r); return GCD(q1, q2); } } int main() { //system("pause"); return 0; }
