func_code_string: #include <bits/stdc++.h>   #pragma comment(linker,  /STACK:16000000 )   using namespace std;   const int Maxn = 1000005;   const int Maxm = 4194304;   const int Inf = 1000000000;   int n, c;   pair<int, int> lef[Maxn], rig[Maxn];   int me[Maxn];   int res[Maxn], rlen;   int st[Maxm];   void Insert(int v, int l, int r, int x, int val) {     if (l == r)       st[v] = val;     else {       int m = l + r >> 1;       if (x <= m)         Insert(2 * v, l, m, x, val);       else         Insert(2 * v + 1, m + 1, r, x, val);       st[v] = max(st[2 * v], st[2 * v + 1]);     }   }   int Get(int v, int l, int r, int a, int b) {     if (l == a && r == b)       return st[v];     else {       int res = -Inf;       int m = l + r >> 1;       if (a <= m) res = max(res, Get(2 * v, l, m, a, min(m, b)));       if (m + 1 <= b) res = max(res, Get(2 * v + 1, m + 1, r, max(m + 1, a), b));       return res;     }   }   bool isNull(const pair<int, int> &p) { return p == pair<int, int>(Inf, -Inf); }   void Print(int l, int r) {     if (l > r) return;     if (l == r)       res[rlen++] = l;     else {       int from = l + 1;       if (!isNull(lef[l])) {         Print(l + 1, lef[l].second);         from = lef[l].second + 1;       }       res[rlen++] = l;       Print(from, r);     }   }   int main() {     scanf( %d %d , &n, &c);     for (int i = 1; i <= n; i++) {       lef[i] = pair<int, int>(Inf, -Inf);       rig[i] = pair<int, int>(Inf, -Inf);     }     int a, b;     char s[10];     while (c--) {       scanf( %d %d %s , &a, &b, s);       if (s[0] ==  L ) {         lef[a].first = min(lef[a].first, b);         lef[a].second = max(lef[a].second, b);       } else {         rig[a].first = min(rig[a].first, b);         rig[a].second = max(rig[a].second, b);       }     }     for (int i = n; i >= 1; i--) {       if (isNull(lef[i]) && isNull(rig[i]))         me[i] = i;       else if (isNull(lef[i]))         if (rig[i].first <= i) {           printf( IMPOSSIBLE n );           return 0;         } else           me[i] = Get(1, 1, n, i + 1, rig[i].second);       else if (isNull(rig[i]))         if (lef[i].first <= i) {           printf( IMPOSSIBLE n );           return 0;         } else {           lef[i].second = Get(1, 1, n, i + 1, lef[i].second);           me[i] = lef[i].second;         }       else if (lef[i].first <= i) {         printf( IMPOSSIBLE n );         return 0;       } else {         lef[i].second = Get(1, 1, n, i + 1, lef[i].second);         if (lef[i].second >= rig[i].first) {           printf( IMPOSSIBLE n );           return 0;         } else           me[i] = Get(1, 1, n, lef[i].second + 1, rig[i].second);       }       Insert(1, 1, n, i, me[i]);     }     Print(1, n);     for (int i = 0; i < rlen; i++)       printf( %d%c , res[i], i + 1 < rlen ?     :   n );     return 0;   }   