feat: 添加字符串哈希处理功能

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/P3953.cpp

@@ -0,0 +1,130 @@
+#include <bitset>
+#include <cstdio>
+#include <deque>
+#include <iostream>
+#include <istream>
+#include <queue>
+#include <vector>
+using ll = int64_t;
+#define sl static inline
+#define printf
+const ll maxm=2e5+5,inf=1e9+7;
+ll n,m,k,p,nt,d[maxm],dp[maxm][57];
+bool isn,vis[maxm][57];
+struct E{
+    ll v,w;
+};
+struct P{
+    ll now,step;
+    inline bool operator<(const P&o)const{
+        return step>o.step;
+    }
+};
+std::vector<std::vector<E>> edg,re;
+std::deque<P>dq;
+
+sl ll dj(){
+    for(ll i=1;i<=n;i++){
+        d[i]=inf;
+    }
+    std::priority_queue<P> pq;
+    pq.emplace(1,0);
+    while(pq.size()){
+        auto[now,step]=pq.top();
+        // printf("dj now=%lld, step=%lld\n",now,step);
+        pq.pop();
+        if(step>=d[now])continue;
+        d[now]=step;
+        for(auto[v,w]:edg[now]){
+            pq.emplace(v,step+w);
+        }
+    }
+    
+    printf("d[]:");
+    for(ll i=1;i<=n;i++){
+        printf("%lld ",d[i]);
+    }
+    printf("\n");
+    return d[n]==inf?-1:d[n];
+}
+
+sl ll dfs(ll u,ll k){
+    if(k<0||k>::k)return 0;
+    if(vis[u][k]){
+        isn=true;
+        return 0;
+    }
+    if(dp[u][k]!=-1){
+        printf("dp[%lld][%lld]=%lld, in temp\n",u,k,dp[u][k]);
+        return dp[u][k];
+    }
+    vis[u][k]=true;
+    ll nans=0;
+    for(auto[v,w]:re[u]){
+        ll nk=d[u]+k-d[v]-w;
+        if(nk<0||nk>::k)continue;
+        nans=(nans+dfs(v, nk))%p;
+        if(isn){
+            vis[u][k]=false;
+            return 0;
+        }
+    }
+    if(u==1){
+        const ll ret= k==0?1:0;
+        printf("dp[%lld][%lld]=%lld u==1\n",u,k,ret);
+        nans=ret;
+    }
+    vis[u][k]=false;
+    printf("dp[%lld][%lld]=%lld\n",u,k,nans);
+    return dp[u][k]=nans;
+}
+
+sl void solve(){
+    printf("NT = %lld\n",++nt);
+    std::cin>>n>>m>>k>>p;
+    isn=false;
+    edg.clear();
+    edg.resize(n+1);
+    re.clear();
+    re.resize(n+1);
+    for(ll i=1;i<=n;i++){
+        for(ll j=0;j<=k;j++){
+            dp[i][j]=-1;
+            vis[i][j]=false;
+        }
+    }
+    for(ll i=1;i<=m;i++){
+        ll u,v,w;
+        std::cin>>u>>v>>w;
+        edg[u].emplace_back(v,w);
+        re[v].emplace_back(u,w);
+    }
+    const ll d = dj();
+    printf("found d=%lld\n",d);
+    if(d==-1){
+        std::cout<<"0\n";
+        return;
+    }
+    // const ll ms=d+k;
+    ll ans=0;
+    for(ll i=0;i<=k;i++){
+        printf("DFS i=%lld----\n",i);
+        ans=(ans+dfs(n,i))%p;
+        if(isn){
+            std::cout<<"-1\n";
+            return;
+        }
+    }
+    std::cout<<ans<<"\n";
+}
+
+int main(){
+    std::iostream::sync_with_stdio(false);
+    std::cin.tie(nullptr);
+
+    ll t;
+    std::cin>>t;
+    while(t--){
+        solve();
+    }
+}

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;
+}