Init

ACMOJ-1717.cpp

@@ -0,0 +1,60 @@
+#include<iostream>
+#include<cstring>
+#include<algorithm>
+#include<cassert>
+#include<string>
+#include<cstdio>
+#include<queue>
+#include<map>
+using namespace std;
+typedef long long LL;
+unordered_map<LL,int> cnt;
+const int maxn=1e6+10;
+LL res;
+int n,m;
+LL a[maxn];
+int main()
+{
+#ifdef local
+	freopen("pro.in", "r", stdin);
+	// freopen("pro.out","w",stdout);
+#endif
+	scanf("%d%d",&n,&m);
+	cnt[0]=1;
+	LL pre=0;
+	for(int i=1;i<=n;i++)
+	{
+		scanf("%lld",&a[i]);
+		pre^=a[i];
+		res+=cnt[pre];
+		cnt[pre]++;
+	}
+	for(int i=2;i<=n;i++) a[i]^=a[i-1];
+	LL xor_sum=0,odd_num=0,max_res,min_res;
+	bool is_first=true;
+	while(m-->0)
+	{
+		int p,x;
+		scanf("%d%d",&p,&x);
+		LL a_before=a[p],a_after=a[p]^x;
+		LL delta=-(cnt[a_before]-1)+cnt[a_after];
+		if(x==0) goto proc;
+		a[p]^=x;
+		cnt[a_before]--;
+		cnt[a_after]++;
+		res+=delta;
+		assert(res>=0);
+		proc:
+		xor_sum^=res;
+		odd_num+=(res&1);
+		if(is_first)
+		{
+			max_res=min_res=res;
+			is_first=false;
+		}
+		max_res=max(max_res,res);
+		min_res=min(min_res,res);
+	}
+	printf("%lld\n%lld\n%lld\n%lld\n",xor_sum,odd_num,max_res,min_res);
+	return 0;
+}