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Submission #306216

# Submission time Handle Problem Language Result Execution time Memory
306216 2020-09-24T22:16:27 Z andremfq 전압 (JOI14_voltage) C++17
100 / 100
 364 ms 10232 KB 
// Ivan Carvalho
// Voltage - JOI SC 2014
#include <bits/stdc++.h>
using namespace std;

typedef pair<int,int> ii;

const int MAXN = 1e5 + 10;
const int MAXM = 2*1e5 + 10;

int e1[MAXM],e2[MAXM],parent[MAXN],connectParent[MAXN],weight[MAXN],N,M,ans;
int possible,last,oldW[MAXM],oldz[MAXM],oldParent[MAXM],oldConnection[MAXM],oldWeight[MAXM],oldPossible[MAXM];

int find(int x){
	if(x == parent[x]) return x;
	return find(parent[x]);
}

int parity(int x){
	if(x == parent[x]) return 0;
	return (connectParent[x] ^ parity(parent[x]));
}

void join(int x,int y){
	
	int w = find(x), z = find(y),px = parity(x),py = parity(y);
	
	if(weight[w] < weight[z]){
		swap(w,z);
		swap(px,py);
		swap(x,y);
	}
	
	last++;
	oldW[last] = w;
	oldz[last] = z;
	oldParent[last] = parent[z];
	oldConnection[last] = connectParent[z];
	oldWeight[last] = weight[w];
	oldPossible[last] = possible;
	
	if(w == z){
		if(px == py) possible = 0;
		return;
	}

	parent[z] = w;
	weight[w] += weight[z];

	if(px == py) connectParent[z] = 1;
	else connectParent[z] = 0;

}

void undo(){
	int w = oldW[last] , z = oldz[last];
	weight[w] = oldWeight[last];
	parent[z] = oldParent[last];
	connectParent[z] = oldConnection[last];
	possible = oldPossible[last];
	last--; 
}

void divide_and_conquer(int lo,int hi){
	
	if(lo == hi){
		if(possible){
			if(find(e1[lo]) != find(e2[lo])) ans++;
			else if(parity(e1[lo]) == parity(e2[lo])) ans++;
		}
		return;
	}
	
	int mid = (lo+hi)/2;
	for(int i = mid + 1;i<=hi;i++){
		join(e1[i],e2[i]);
	}
	
	divide_and_conquer(lo,mid);
	
	for(int i = mid + 1;i<=hi;i++){
		undo();
	}
	
	for(int i = lo;i<=mid;i++){
		join(e1[i],e2[i]);
	}
	
	divide_and_conquer(mid+1,hi);
	
	for(int i = lo;i<=mid;i++){
		undo();
	}

}

int main(){
	
	scanf("%d %d",&N,&M);
	
	for(int i = 1;i<=N;i++){
		parent[i] = i;
		weight[i] = 1;
		connectParent[i] = 0;
	}
	
	possible = 1;
	
	for(int i = 1;i<=M;i++){
		scanf("%d %d",&e1[i],&e2[i]);
	}
	
	divide_and_conquer(1,M);
	
	printf("%d\n",ans);
	
	return 0;

}

Compilation message

voltage.cpp: In function 'int main()':
voltage.cpp:99:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   99 |  scanf("%d %d",&N,&M);
      |  ~~~~~^~~~~~~~~~~~~~~
voltage.cpp:110:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  110 |   scanf("%d %d",&e1[i],&e2[i]);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 512 KB Output is correct
2 Correct 2 ms 512 KB Output is correct
3 Correct 2 ms 384 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 2 ms 512 KB Output is correct
6 Correct 2 ms 512 KB Output is correct
7 Correct 2 ms 512 KB Output is correct
8 Correct 2 ms 512 KB Output is correct
9 Correct 2 ms 512 KB Output is correct
10 Correct 2 ms 512 KB Output is correct
11 Correct 2 ms 512 KB Output is correct
12 Correct 2 ms 512 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 83 ms 5880 KB Output is correct
2 Correct 195 ms 5904 KB Output is correct
3 Correct 83 ms 5884 KB Output is correct
4 Correct 186 ms 5884 KB Output is correct
5 Correct 13 ms 896 KB Output is correct
6 Correct 179 ms 5752 KB Output is correct
7 Correct 200 ms 5880 KB Output is correct
8 Correct 200 ms 5880 KB Output is correct

Subtask #3
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 48 ms 5368 KB Output is correct
2 Correct 58 ms 5760 KB Output is correct
3 Correct 57 ms 5752 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 142 ms 4728 KB Output is correct
6 Correct 137 ms 5752 KB Output is correct
7 Correct 189 ms 5880 KB Output is correct
8 Correct 180 ms 5752 KB Output is correct
9 Correct 189 ms 5760 KB Output is correct
10 Correct 184 ms 5752 KB Output is correct
11 Correct 133 ms 5752 KB Output is correct
12 Correct 166 ms 5880 KB Output is correct

Subtask #4
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 104 ms 9336 KB Output is correct
2 Correct 124 ms 10120 KB Output is correct
3 Correct 1 ms 1536 KB Output is correct
4 Correct 194 ms 6136 KB Output is correct
5 Correct 207 ms 6268 KB Output is correct
6 Correct 183 ms 6264 KB Output is correct
7 Correct 335 ms 10104 KB Output is correct
8 Correct 309 ms 10104 KB Output is correct
9 Correct 302 ms 10232 KB Output is correct
10 Correct 291 ms 10104 KB Output is correct
11 Correct 230 ms 10232 KB Output is correct
12 Correct 297 ms 10232 KB Output is correct
13 Correct 255 ms 10104 KB Output is correct
14 Correct 364 ms 10232 KB Output is correct
15 Correct 293 ms 10232 KB Output is correct
16 Correct 281 ms 9976 KB Output is correct
17 Correct 319 ms 10192 KB Output is correct
18 Correct 244 ms 10108 KB Output is correct