Submission #121248

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
121248	2019-06-26T09:08:32 Z	win11905	Flood (IOI07_flood)	C++11	Compilation error	0 ms	0 KB

flood

#include <bits/stdc++.h>
#define pii pair<int, int>
#define x first
#define y second
using namespace std;

const int N = 2e5+5;

int n, m;
int x[N], y[N];
int s[N], t[N];
int za[N], zb[N];
bool state[N][4];
int idx;
map<pii, int> Mp;

int par[N<<1];

int find(int u) { return par[u] = par[u] == u ? u : find(par[u]); }

void merge(int a, int b, int c, int d) {
    int u = Mp[pii(a, b)], v = Mp[pii(c, d)];
    par[find(u)] = find(v);
}

int main() {
    iota(par, par+(N<<1), 0);
    scanf("%d", &n);
    int mnx = 1e9, st;
    for(int i = 0; i < n; ++i) {
        scanf("%d %d", x+i, y+i);
        Mp[pii(x[i], y[i])] = ++idx;
        Mp[pii(x[i]+1, y[i])] = ++idx;
        Mp[pii(x[i], y[i]+1)] = ++idx;
        Mp[pii(x[i]+1, y[i]+1)] = ++idx;
        if(x[i] < mnx) mnx = x[i], st = i;
    }
    scanf("%d", &m);
    for(int i = 0; i < m; ++i) {
        scanf("%d %d", s+i, t+i), s[i]--, t[i]--;
        if(x[s[i]] > x[t[i]]) swap(s[i], t[i]);
        if(y[s[i]] > y[t[i]]) swap(s[i], t[i]);
        if(x[s[i]] != x[t[i]]) {
            state[s[i]][1] = state[t[i]][3] = true;
            merge(x[s[i]]+1, y[s[i]], x[t[i]], y[t[i]]);
            merge(x[s[i]]+1, y[s[i]]+1, x[t[i]], y[t[i]]+1);            
        } else {
            state[s[i]][0] = state[t[i]][2] = true;
            merge(x[s[i]], y[s[i]]+1, x[t[i]], y[t[i]]);
            merge(x[s[i]]+1, y[s[i]]+1, x[t[i]]+1, y[t[i]]);
        }
    }
    for(int i = 0; i < n; ++i) {
        if(!state[i][0]) merge(x[i], y[i]+1, x[i]+1, y[i]+1);
        if(!state[i][1]) merge(x[i]+1, y[i], x[i]+1, y[i]+1);
        if(!state[i][2]) merge(x[i], y[i], x[i]+1, y[i]);
        if(!state[i][3]) merge(x[i], y[i], x[i], y[i]+1);
    }
    for(int i = 0; i < m; ++i) {
        int a, b;
        if(x[s[i]] != x[t[i]]) 
            a = find(Mp[pii(x[s[i]]+1, y[s[i]])]), b = find(Mp[pii(x[s[i]]+1, y[s[i]]+1)]);
        else 
            a = find(Mp[pii(x[s[i]], y[s[i]]+1)]), b = find(Mp[pii(x[s[i]]+1, y[s[i]]+1)]);
        za[i] = a, zb[i] = b;
        g[a].emplace_back(i), g[b].emplace_back(i);
    }
    int start = find(Mp[pii(x[st], y[st])]);
    Mp.clear();
    
}

Compilation message

flood.cpp: In function 'int main()':
flood.cpp:66:9: error: 'g' was not declared in this scope
         g[a].emplace_back(i), g[b].emplace_back(i);
         ^
flood.cpp:68:9: warning: unused variable 'start' [-Wunused-variable]
     int start = find(Mp[pii(x[st], y[st])]);
         ^~~~~
flood.cpp:28:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
flood.cpp:31:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", x+i, y+i);
         ~~~~~^~~~~~~~~~~~~~~~~~~
flood.cpp:38:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &m);
     ~~~~~^~~~~~~~~~
flood.cpp:40:41: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", s+i, t+i), s[i]--, t[i]--;
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~