Submission #1447732

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Source Code Expand

#include <bits/stdc++.h>

using namespace std ;

int n ; 

const int MAXN = 100010 ; 

int fa[MAXN], fb[MAXN] ;

vector<int> ga[MAXN], gb[MAXN] ; 


int x[MAXN], y[MAXN] ; 

struct Edge {
		int l, r, bel, typ, t2, nxt ; 
} e[MAXN << 2] ;

bool vis[MAXN << 2] ; 

int ecnt = 1, hed[MAXN] ; 

int due[MAXN] ; 

void addedge(int l, int r, int bel, int typ, int t2) { 
		++ ecnt, e[ecnt].l = l, e[ecnt].r = r, e[ecnt].nxt = hed[l], e[ecnt].bel = bel, e[ecnt].typ = typ, e[ecnt].t2 = t2, hed[l] = ecnt; 
		due[l] ++ ; 
}

void adde(int l, int r, int bel, int typ, int t2) { 
		addedge(l, r, bel, typ, t2) ;
		addedge(r, l, bel, typ ^ 1, t2) ; 
}

void Build() {
		for (int i = 1; i <= n; i ++) { 
				adde(i, fa[i] == -1 ? n + 1 : fa[i], i, 0, 0) ; 
				adde(i, fb[i] == -1 ? n + 1 : fb[i], i, 1, 1) ; 
		}
}

void Dfs(int X) { 
		for (int i = hed[X]; i; i = hed[X]) {
				hed[X] = e[i].nxt ; 
				if (vis[i ^ 1]) continue ; 
				vis[i] = 1;  
				Dfs(e[i].r) ; 
				if (e[i].t2 == 0) { 
						x[e[i].bel] = e[i].typ ? 1 : -1 ; 
				}
				else y[e[i].bel] = e[i].typ ? 1 : -1 ; 
				if (!hed[X]) break ;
		}
}

int main() {

		scanf("%d", &n) ; 
		for (int i = 1; i <= n; i ++) { 
				scanf("%d", &fa[i]) ; 
				if (fa[i] != -1) ga[fa[i]].push_back(i) ; 
		}
		for (int i = 1; i <= n; i ++) { 
				scanf("%d", &fb[i]) ; 
				if (fb[i] != -1) gb[fb[i]].push_back(i) ; 
		}
		Build() ; 
		for (int i = 1; i <= n; i ++) { 
				if (due[i] & 1) {
						puts("IMPOSSIBLE") ; 
						return 0 ; 
				}
		}
		puts("POSSIBLE");  	
		Dfs(n + 1) ; 
		for (int i = 1; i <= n; i ++) { 
				int tmp = x[i] ; 
				for (int j = 0; j < ga[i].size(); j ++) { 
						tmp -= x[ga[i][j]] ; 
				}
				printf("%d%c", tmp, i == n ? 10 : ' '); 
		}
}







	

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:59:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &n) ; 
                   ^
./Main.cpp:61:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &fa[i]) ; 
                         ^
./Main.cpp:65:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &fb[i]) ; 
                         ^

Judge Result