From 197e613574eff6e75ace4b4cae7d8a646e7adce9 Mon Sep 17 00:00:00 2001
From: Zengtudor <zengtudor@outlook.com>
Date: Wed, 5 Nov 2025 19:02:08 +0800
Subject: [PATCH] =?UTF-8?q?feat:=20=E6=B7=BB=E5=8A=A0=E5=AD=97=E7=AC=A6?=
 =?UTF-8?q?=E4=B8=B2=E5=93=88=E5=B8=8C=E5=A4=84=E7=90=86=E5=8A=9F=E8=83=BD?=
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实现基于Z算法的字符串哈希处理，用于计算特定模式的出现次数和统计字符出现奇偶性。包含输入处理、Z数组计算和结果统计逻辑。
---
 src/11/5/qzhash.cpp | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 src/11/5/qzhash.cpp

diff --git a/src/11/5/qzhash.cpp b/src/11/5/qzhash.cpp
new file mode 100644
index 0000000..efe52b4
--- /dev/null
+++ b/src/11/5/qzhash.cpp
@@ -0,0 +1,43 @@
+#include<bits/stdc++.h>
+using namespace std;
+typedef long long ll;
+int T,n,Z[2001000],cnt1[30],cnt2[30],sum[30],CN,BN,nown,sumn,nown2;
+ll res;
+char s[2001000];
+int main(){
+//	freopen("string.in","r",stdin);
+//	freopen("string.out","w",stdout);
+	scanf("%d",&T);
+	while(T--){
+		scanf("%s",s),n=strlen(s),memset(sum,0,sizeof(sum)),memset(cnt1,0,sizeof(cnt1)),memset(cnt2,0,sizeof(cnt2)),res=CN=BN=0;
+		for(int i=0;i<n;i++)cnt1[s[i]-'a']^=1;
+		for(int i=0;i<26;i++)CN+=cnt1[i];
+		int Centre=-1,Rpos=-1;
+		for(int i=1;i<n;i++){
+			if(i<=Rpos)Z[i]=min(Z[i-Centre],Rpos-i+1);
+			else Z[i]=0;
+			while(i+Z[i]<n&&s[Z[i]]==s[i+Z[i]])Z[i]++;
+			if(i+Z[i]>Rpos)Centre=i,Rpos=i+Z[i]-1;
+		}
+//		for(int i=1;i<n;i++)printf("%d ",Z[i]);puts("");
+		nown=CN,nown2=sumn=0;
+		for(int i=1;i<n;i++){
+			if(cnt1[s[i-1]-'a'])sumn-=sum[nown--];
+			else sumn+=sum[++nown];
+			cnt1[s[i-1]-'a']^=1;
+			int tot=min(Z[i],n-i-1)/i+1;
+			int N1=(tot+1)>>1,N2=(tot)>>1;
+//			printf("%d:%d %d\n",tot,N1,N2);
+			res+=1ll*sumn*N1;
+			if(cnt2[s[i-1]-'a'])nown2--;
+			else nown2++;
+			cnt2[s[i-1]-'a']^=1;
+			sum[nown2]++;
+			if(nown2<=nown)sumn++;
+			res+=1ll*BN*N2;
+			if(nown2<=CN)BN++;
+		}
+		printf("%lld\n",res);
+	}
+	return 0;
+}