delete pics to save space

history_source/ccf 基础篇/U6/6.5.5.cpp

@@ -0,0 +1,48 @@
+#include<cstdio>
+#include<algorithm>
+using namespace std;
+bool cmp(int a,int b)
+{
+	return a<=b;
+}
+int *find(int *left,int *right,int n)
+{
+	int *mid,*p;
+	p=left;
+	bool f=1;
+	while(left<right)
+	{
+		mid=left+(right-left)/2;
+		if(*mid==n) 
+		{
+			f=0;
+			left=mid;
+			break;
+		}
+		if(*mid<n) left=mid;
+		else right=mid;
+	}
+	if(f) return 0;
+	if(*left!=n) return 0;
+	while(*left==n&&left>=p) left--;
+	left++;
+	return left;
+}
+int main()
+{
+	int n,c;
+	int ans=0;
+	scanf("%d%d",&n,&c);
+	int num[n];
+	for(int i=0;i<n;i++) scanf("%d",num+i);
+	sort(num,num+n,cmp);
+	int x,*p;
+	for(int i=0;i<n;i++)
+	{
+		x=num[i]-c;
+		p=find(num,num+n,x);
+		if(p!=0) while(*p==x&&p<num+n) ans++,p++;
+	}
+	printf("%d\n",ans);
+	return 0;
+}