Submission #992463

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Source Code Expand

#include <cstdio>
#include <cstdlib>

int N,M;
int Xs[100008];
int cmp(const void *ka,const void *kb) {
	int a=*(int *)ka;
	int b=*(int *)kb;
	return a-b;
}
int modM_solo[100008];
int modM_pair[100008];
int getmin(int a,int b) {
	if(a>b) return b;
	return a;
}
int add(int a,int b,int c,int d) {
	int ret=getmin(b,d);
	b-=ret;
	d-=ret;
	if(b>0) {
		int temp=getmin(b,c*2);
		ret+=temp+a+(c*2-temp)/2;
	} else {
		int temp=getmin(d,a*2);
		ret+=temp+c+(a*2-temp)/2;
	}
	return ret;
}
int main() {
	scanf("%d%d",&N,&M);
	for(int i=0;i<N;i++) scanf("%d",&Xs[i]);
	qsort(Xs,N,sizeof(int),cmp);
	for(int i=0;i<N;i++) {
		if(Xs[i]==Xs[i+1]) {
			modM_pair[Xs[i]%M]++;
			i++;
		} else {
			modM_solo[Xs[i]%M]++;
		}
	}
	int sol=0;
	//case 0
	sol+=modM_pair[0]+modM_solo[0]/2;
	//case M/2
	if(M%2==0) sol+=modM_pair[M/2]+modM_solo[M/2]/2;
	for(int i=1;i<(M+1)/2;i++) sol+=add(modM_pair[i],modM_solo[i],modM_pair[M-i],modM_solo[M-i]);
	printf("%d\n",sol);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:31:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&N,&M);
                     ^
./Main.cpp:32:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  for(int i=0;i<N;i++) scanf("%d",&Xs[i]);
                                         ^

Judge Result