class SegTree: def __init__(self, init_val, ide_ele, segfunc): self.n = len(init_val) self.num = 2**(self.n-1).bit_length() self.ide_ele = ide_ele self.segfunc = segfunc self.seg = [ide_ele]*2*self.num # set_val for i in range(self.n): self.seg[i+self.num] = init_val[i] # built for i in range(self.num-1, 0, -1): self.seg[i] = self.segfunc(self.seg[2*i], self.seg[2*i+1]) def update(self, k, x): k += self.num self.seg[k] = x while k: k = k >> 1 self.seg[k] = self.segfunc(self.seg[2*k], self.seg[2*k+1]) def query(self, l, r): if r <= l: return self.ide_ele l += self.num r += self.num lres = self.ide_ele rres = self.ide_ele while l < r: if r & 1: r -= 1 rres = self.segfunc(self.seg[r], rres) if l & 1: lres = self.segfunc(lres, self.seg[l]) l += 1 l = l >> 1 r = r >> 1 res = self.segfunc(lres, rres) return res def __str__(self): # for debug arr = [self.query(i,i+1) for i in range(self.n)] return str(arr) INF = 10**18 import sys import io, os input = io.BytesIO(os.read(0,os.fstat(0).st_size)).readline n, q = map(int, input().split()) LR = [] for i in range(q): l, r, b = map(int, input().split()) l, r = l-1, r-1 LR.append((l, r, b)) seg = SegTree([INF]*n, INF, min) LR.sort(key=lambda x: x[0]) #print(LR) for l, r, b in LR: x = seg.query(l, r+1) if x < b: print(-1) exit() seg.update(l, b) A = [] for i in range(n): a = seg.query(i, i+1) if a == INF: A.append(10**9) else: A.append(a) print(*A)