see you again
#include<bits/stdc++.h>
using namespace std;
int n,m,x,y,v,Lok[500010],Rok[500010],Lban[500010],Rban[500010],pre[500010],ans[500010];
bool findans;
set<int>st;
template <typename T>
inline void read(T &ans) {
ans=0;
char ch=getchar(),f=1;
for(; ch<'0'||ch>'9'; ch=getchar())
if(ch=='-')f=0;
for(; ch>='0'&&ch<='9'; ch=getchar())
ans=(((ans<<2)+ans)<<1)+(ch^'0');
ans=f?ans:-ans;
}
void write(int x) {
if(x>=10)write(x/10);
putchar(x%10+'0');
}
int main() {
read(n);
read(m);
for(int i=0; i<=n; i++)st.insert(i);
for(int i=0; i<=n+1; i++)Lok[i]=0,Rok[i]=n,Lban[i]=n+1,Rban[i]=-1;
for(int i=1; i<=m; i++) {
read(x);
read(y);
read(v);
if(v)Lok[v-1]=max(Lok[v-1],x),Rok[v-1]=min(Rok[v-1],y),Lban[v]=min(Lban[v],x),Rban[v]=max(Rban[v],y);
else pre[x]++,pre[y+1]--;
}
for(int i=n; i>=0; i--)Lok[i]=max(Lok[i],Lok[i+1]),Rok[i]=min(Rok[i],Rok[i+1]);
for(int i=0; i<=n; i++) {
pre[i]+=pre[i-1];
if(Lok[0]<=i&&i<=Rok[0]&&pre[i]==0) {
ans[i]=0;
st.erase(i);
break;
}
}
for(int i=1; i<=n; i++) {
set<int>::iterator t=st.lower_bound(Lok[i]);
if(t!=st.end()&&*t<=Rok[i]&&(Lban[i]>*t||*t>Rban[i]))ans[*t]=i,st.erase(t);
else if(Rban[i]!=-1) {
t=st.lower_bound(Rban[i]+1);
if(t!=st.end()&&*t<=Rok[i])ans[*t]=i,st.erase(t);
}
}
if(!st.empty()) {
printf("-1\n");
return 0;
}
for(int i=0; i<=n; i++)write(ans[i]),putchar(' ');
printf("\n");
return 0;
}