import sys; input = sys.stdin.buffer.readline sys.setrecursionlimit(10**7) from collections import defaultdict con = 10 ** 9 + 7; INF = float("inf") def getlist(): return list(map(int, input().split())) class lazySegTree(object): def __init__(self, N): self.N = N self.LV = (N - 1).bit_length() self.N0 = 2 ** self.LV self.initVal = 0 self.data = [0] * (2 * self.N0) self.lazy = [0] * (2 * self.N0) def calc(self, a, b): return a + b def initialize(self, A): for i in range(self.N): self.data[self.N0 - 1 + i] = A[i] for i in range(self.N0 - 2, -1, -1): self.data[i] = self.calc(self.data[2 * i + 1], self.data[2 * i + 2]) def gindex(self, l, r): L = (l + self.N0) >> 1; R = (r + self.N0) >> 1 lc = 0 if l & 1 else (L & -L).bit_length() rc = 0 if r & 1 else (R & -R).bit_length() for i in range(self.LV): if rc <= i: yield R if L < R and lc <= i: yield L L >>= 1; R >>= 1 def propagates(self, *ids): for i in reversed(ids): v = self.lazy[i - 1] if not v: continue self.lazy[2 * i - 1] += v; self.lazy[2 * i] += v self.data[2 * i - 1] += v; self.data[2 * i] += v self.lazy[i - 1] = 0 def update(self, l, r, x): *ids, = self.gindex(l, r + 1) self.propagates(*ids) L = self.N0 + l; R = self.N0 + r + 1 while L < R: if R & 1: R -= 1 self.lazy[R - 1] += x; self.data[R - 1] += x if L & 1: self.lazy[L - 1] += x; self.data[L - 1] += x L += 1 L >>= 1; R >>= 1 for i in ids: self.data[i - 1] = self.calc(self.data[2 * i - 1], self.data[2 * i]) def query(self, l, r): self.propagates(*self.gindex(l, r + 1)) L = self.N0 + l; R = self.N0 + r + 1 s = self.initVal while L < R: if R & 1: R -= 1 s = self.calc(s, self.data[R - 1]) if L & 1: s = self.calc(s, self.data[L - 1]) L += 1 L >>= 1; R >>= 1 return s #処理内容 def main(): N = int(input()) A = getlist() for i in range(N): if A[i] > i + 1: print("No") return lSeg = lazySegTree(N + 1) lSeg.initialize([0] + A) for i in range(N, 0, -1): val = lSeg.query(i, i) if val % i != 0: print("No") return x = int(val // i) lSeg.update(0, i - 1, x) print("Yes") if __name__ == '__main__': main()