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  • T25990 [Wind Festival]Running In The Sky

    T25990 [Wind Festival]Running In The Sky

    题目背景
    [Night - 20:02[Night−20:02 P.M.]P.M.]

    夜空真美啊……但是……快要结束了呢……

    题目描述
    一天的活动过后,所有学生都停下来欣赏夜空下点亮的风筝。 CurtisCurtis NishikinoNishikino 想要以更近的视角感受一下,所以她跑到空中的风筝上去了(这对于一个妹子来说有点匪夷所思)! 每只风筝上的灯光都有一个亮度 k_ik
    i
    ​ . 由于风的作用,一些风筝缠在了一起。但是这并不会破坏美妙的气氛,缠在一起的风筝会将灯光汇聚起来,形成更亮的光源!

    CurtisCurtis NishikinoNishikino 已经知道了一些风筝间的关系,比如给出一对风筝 (a,b)(a,b) , 这意味着她可以从 aa 跑到 bb 上去,但是不能返回。

    现在,请帮她找到一条路径(她可以到达一只风筝多次,但只在第一次到达时她会去感受上面的灯光), 使得她可以感受到最多的光亮。同时请告诉她这条路径上单只风筝的最大亮度,如果有多条符合条件的路径,输出能产生最大单只风筝亮度的答案。


    Tarjan缩点途中处理圈内最大值和圈内和,变成DAG然后dp就好

    Code

    #include<iostream>
    #include<cstdio>
    #include<queue>
    #include<cstring>
    #include<algorithm>
    typedef long long LL;
    using namespace std;
    int RD(){
        int out = 0,flag = 1;char c = getchar();
        while(c < '0' || c >'9'){if(c == '-')flag = -1;c = getchar();}
        while(c >= '0' && c <= '9'){out = out * 10 + c - '0';c = getchar();}
        return flag * out;
        }
    const int maxn = 1000019,INF = 1e9;
    int head[maxn][2],nume;
    struct Node{
        int v,dis,nxt;
        }E[maxn << 3][2];
    void add(int u,int v,int dis,int o){
        E[++nume][o].nxt = head[u][o];
        E[nume][o].v = v;
        E[nume][o].dis = dis;
        head[u][o] = nume;
        }
    int num,nr,v[maxn];
    int DFN[maxn],LOW[maxn],INDEX;
    int S[maxn],top;
    bool ins[maxn];
    int col[maxn],numc,vc[maxn],MAX[maxn];
    void Tarjan(int u){
        DFN[u] = LOW[u] = ++INDEX;
        S[++top] = u;ins[u] = 1;
        for(int i = head[u][0];i;i = E[i][0].nxt){
            int v = E[i][0].v;
            if(!DFN[v]){Tarjan(v);LOW[u] = min(LOW[u],LOW[v]);}
            else if(ins[v])LOW[u] = min(LOW[u],DFN[v]);
            }
        if(DFN[u] == LOW[u]){
            numc++;
            while(S[top + 1] != u){
                col[S[top]] = numc;
                vc[numc] += v[S[top]];
                MAX[numc] = max(MAX[numc],v[S[top]]);
                ins[S[top--]] = 0;
                }
            }
        }
    int fam[maxn];
    int dp[maxn];
    int DP(int u){
        if(dp[u] > 0)return dp[u];
        dp[u] = vc[u];int now = 0;
        for(int i = head[u][1];i;i = E[i][1].nxt){
            int v = E[i][1].v;
            if(DP(v) > now){
                now = DP(v);
                fam[u] = fam[v];
                }
            }
        dp[u] += now;
        fam[u] = max(fam[u],MAX[u]);
        return dp[u];
        }
    int main(){
        num = RD();nr = RD();
        for(int i = 1;i <= num;i++)v[i] = RD();
        for(int i = 1;i <= nr;i++){
            int u = RD(),v = RD();
            add(u,v,1,0);
            }
        for(int i = 1;i <= num;i++)if(!DFN[i])Tarjan(i);
        for(int u = 1;u <= num;u++){
            for(int i = head[u][0];i;i = E[i][0].nxt){
                int v = E[i][0].v;
                if(col[u] != col[v])add(col[v],col[u],1,1);
                }
            }
        int ans = 0,maxx = 0;
        for(int i = 1;i <= numc;i++){
            int cmp = DP(i);
            if(cmp > ans){
                ans = cmp;
                maxx = fam[i];
                }
            else if(cmp == ans)maxx = max(maxx,fam[i]);
            }
        printf("%d %d
    ",ans,maxx);
        return 0;
        }
    

    Upd 两分钟以后

    其实之前结构体的写法是完全没有错的!!!,学会了重载,这里贴一下

    #include<iostream>
    #include<cstdio>
    #include<queue>
    #include<cstring>
    #include<algorithm>
    typedef long long LL;
    using namespace std;
    int RD(){
        int out = 0,flag = 1;char c = getchar();
        while(c < '0' || c >'9'){if(c == '-')flag = -1;c = getchar();}
        while(c >= '0' && c <= '9'){out = out * 10 + c - '0';c = getchar();}
        return flag * out;
        }
    const int maxn = 1000019,INF = 1e9;
    int head[maxn][2],nume;
    struct Node{
        int v,dis,nxt;
        }E[maxn << 3][2];
    void add(int u,int v,int dis,int o){
        E[++nume][o].nxt = head[u][o];
        E[nume][o].v = v;
        E[nume][o].dis = dis;
        head[u][o] = nume;
        }
    int num,nr,v[maxn];
    int DFN[maxn],LOW[maxn],INDEX;
    int S[maxn],top;
    bool ins[maxn];
    int col[maxn],numc,vc[maxn],MAX[maxn];
    void Tarjan(int u){
        DFN[u] = LOW[u] = ++INDEX;
        S[++top] = u;ins[u] = 1;
        for(int i = head[u][0];i;i = E[i][0].nxt){
            int v = E[i][0].v;
            if(!DFN[v]){Tarjan(v);LOW[u] = min(LOW[u],LOW[v]);}
            else if(ins[v])LOW[u] = min(LOW[u],DFN[v]);
            }
        if(DFN[u] == LOW[u]){
            numc++;
            while(S[top + 1] != u){
                col[S[top]] = numc;
                vc[numc] += v[S[top]];
                MAX[numc] = max(MAX[numc],v[S[top]]);
                ins[S[top--]] = 0;
                }
            }
        }
    int ing[maxn],outg[maxn];
    struct Dp{
        int sum,maxx;
        Dp (int sum,int maxx):sum(sum), maxx(maxx){}
        Dp(){}
        bool operator > (const Dp &a)const{
            if(a.sum != sum)return sum > a.sum;
            return maxx > a.maxx;
            }
        Dp operator + (const Dp &a){
            Dp ans;
            ans.sum = sum + a.sum;
            ans.maxx = max(maxx,a.maxx);
            return ans;
            }
        }dp[maxn];
    Dp DP(int u){
        if(dp[u].sum > 0)return dp[u];
        dp[u] = Dp(vc[u],MAX[u]);
        Dp max = dp[u];
        for(int i = head[u][1];i;i = E[i][1].nxt){
            int v = E[i][1].v;
            Dp temp = DP(v);
            if(temp + dp[u] > max)max = temp + dp[u];
            }
        dp[u] = max;
        return dp[u];
        }
    int main(){
        num = RD();nr = RD();
        for(int i = 1;i <= num;i++)v[i] = RD();
        for(int i = 1;i <= nr;i++){
            int u = RD(),v = RD();
            add(u,v,1,0);
            }
        for(int i = 1;i <= num;i++)if(!DFN[i])Tarjan(i);
        for(int u = 1;u <= num;u++){
            for(int i = head[u][0];i;i = E[i][0].nxt){
                int v = E[i][0].v;
                if(col[u] != col[v])add(col[v],col[u],1,1);
                }
            }
        Dp ans = Dp(0,0);
        for(int i = 1;i <= numc;i++){
            if(DP(i) > ans)ans = DP(i);
            }
        //for(int i = 1;i <= numc;i++)printf("col=%d,sum=%d,max=%d
    ",i,dp[i].sum,dp[i].maxx);
        printf("%d %d
    ",ans.sum,ans.maxx);
        //printf("judge=%d
    ",Dp(100000,10000) > Dp(0,0));
        return 0;
        }
    
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  • 原文地址:https://www.cnblogs.com/Tony-Double-Sky/p/9288802.html
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