#include void add_BIT(int N, int BIT[], int i, int k) { while (i <= N) { BIT[i] += k; i += (i & -i); } } int sum_BIT(int BIT[], int r) { int sum = 0; while (r > 0) { sum += BIT[r]; r -= (r & -r); } return sum; } typedef struct { int left, right, max, la, lb; } lazy_seg_node; void init_node(lazy_seg_node v[], int k, int l, int r) { v[k].left = l; v[k].right = r; v[k].max = 0; v[k].la = 3; v[k].lb = 0; if (l < r) { init_node(v, k << 1, l, (l + r) / 2); init_node(v, (k << 1) ^ 1, (l + r) / 2 + 1, r); } } void update_max_to_root(lazy_seg_node v[], int k) { int j; for (j = k >> 1; j > 0; k = j, j >>= 1) v[j].max = (v[k].max > v[k^1].max)? v[k].max: v[k^1].max; } void push_update_below(lazy_seg_node v[], int k) { int j; if (v[k].left == v[k].right || (v[k].la == 3 && v[k].lb == 0)) return; j = k << 1; v[j].max = v[j].max & v[k].la ^ v[k].lb; v[j].la &= v[k].la; v[j].lb = v[j].lb & v[k].la ^ v[k].lb; j ^= 1; v[j].max = v[j].max & v[k].la ^ v[k].lb; v[j].la &= v[k].la; v[j].lb = v[j].lb & v[k].la ^ v[k].lb; v[k].la = 3; v[k].lb = 0; } void update_segment(lazy_seg_node v[], int k, int l, int r, int a, int b) { if (r < v[k].left || v[k].right < l) return; else if (l <= v[k].left && v[k].right <= r) { v[k].max = v[k].max & a ^ b; v[k].la &= a; v[k].lb = v[k].lb & a ^ b; update_max_to_root(v, k); } else { push_update_below(v, k); update_segment(v, k << 1, l, r, a, b); update_segment(v, (k << 1) ^ 1, l, r, a, b); } } int BS_left(lazy_seg_node v[], int k, int l, int r, int x) { int tmp; if (v[k].max < x || r < v[k].left || v[k].right < l) return r + 1; else if (v[k].left == v[k].right) return v[k].left; else { push_update_below(v, k); tmp = BS_left(v, k << 1, l, r, x); if (tmp <= r) return tmp; else return BS_left(v, (k << 1) ^ 1, l, r, x); } } int main() { int i, N, P[200001], P_inv[200001]; scanf("%d", &N); for (i = 1; i <= N; i++) scanf("%d", &(P[i])); for (i = 1; i <= N; i++) P_inv[P[i]] = i; int j, k, l, BIT[200001] = {}, start[200001] = {}; lazy_seg_node v[524288]; init_node(v, 1, 1, N); for (i = 1; i <= N; i++) { j = P_inv[i]; k = sum_BIT(BIT, j - 1); add_BIT(N, BIT, j, 1); update_segment(v, 1, j, N, 3, 1); if (k % 2 == 0) { if (i == 1 || start[i-1] > 0) start[i] = i; update_segment(v, 1, 1, j - 1, 1, 0); } else update_segment(v, 1, j + 1, N, 1, 0); if (start[i] == 0) { l = BS_left(v, 1, 1, N, 3); if (l <= N) start[i] = P[l]; } if (i == 1 || start[i-1] > 0) update_segment(v, 1, j, j, 3, 2); } if (start[N] == 0) { printf("No\n"); fflush(stdout); return 0; } int ans[200001][2]; for (i = N, k = N; i >= 1; i--) { j = start[i]; ans[k][0] = j; ans[k--][1] = sum_BIT(BIT, P_inv[j]); add_BIT(N, BIT, P_inv[j], -1); for (; i > j; i--) { ans[k][0] = i; ans[k--][1] = sum_BIT(BIT, P_inv[i]); add_BIT(N, BIT, P_inv[i], -1); } } printf("Yes\n"); for (i = 1; i <= N; i++) printf("%d %d\n", ans[i][0], ans[i][1]); fflush(stdout); return 0; }