BZOJ3362 [Usaco2004 Feb]Navigation Nightmare 导航噩梦

标题效果：自脑补。

思维：与维护两个维度和可设置为检查右。

注意，标题给予一堆关系的。我们应该加入两对关系。

Code:

#include
<cstdio>

#include
<cstring>

#include
<cctype>

#include
<iostream>

#include
<algorithm>

using

namespace
std;

 

#define
N 40010

int

n, m;

struct

UnionSet {

    int

root[N], dis[N];

    void

reset() {

        int

i;

        for(i
= 1; i <= n; ++i)

            root[i]
= i, dis[i] = 0;

    }

    int

find(int

x) {

        static

int
stack[N];

        int

top = 0;

        for(;
x != root[x]; x = root[x])

            stack[++top]
= x;

        for(int

i = top - 1; i >= 1; --i)

            dis[stack[i]]
+= dis[stack[i + 1]], root[stack[i]] = x;

        return

x;

    }

}Set[2];

 

#define
K 10010

struct

Ask {

    int

u, v, tclock, lab;

    void

read(int

_) {

        lab
= _;

        scanf("%d%d%d",
&u, &v, &tclock);

    }

    bool

operator < (const

Ask &B) const

{

        return

tclock < B.tclock;

    }

}S[K];

int

ans[K];

 

#define
M 40010

int

u[M], v[M], d[M];

bool

vec[M];

 

#define
_abs(x) ((x)>0?(x):-(x))

 

int

main() {

    #ifndef
ONLINE_JUDGE

    freopen("tt.in",
"r",
stdin);

    #endif


     

    scanf("%d%d",
&n, &m);

     

    register

int
i, j;

     

    int

a, b, x;

    char

s[10];

    for(i
= 1; i <= m; ++i) {

        scanf("%d%d%d%s",
&a, &b, &x, s);

        d[i]
= x;

        if

(s[0] == 'E')

            u[i]
= a, v[i] = b, vec[i] = 0;

        else

if
(s[0] == 'W')

            u[i]
= b, v[i] = a, vec[i] = 0;

        else

if
(s[0] == 'N')

            u[i]
= a, v[i] = b, vec[i] = 1;

        else

            u[i]
= b, v[i] = a, vec[i] = 1;

    }

     

    int

Q;

    scanf("%d",
&Q);

    for(i
= 1; i <= Q; ++i)

        S[i].read(i);

    sort(S
+ 1, S + Q + 1);

     

    Set[0].reset(),
Set[1].reset();

     

    int

ra, rb;

    j
= 1;

    for(i
= 1; i <= m; ++i) {

        ra
= Set[vec[i]].find(u[i]);

        rb
= Set[vec[i]].find(v[i]);

        Set[vec[i]].root[ra]
= rb;

        Set[vec[i]].dis[ra]
= d[i] + Set[vec[i]].dis[v[i]] - Set[vec[i]].dis[u[i]];

         

        ra
= Set[1 - vec[i]].find(u[i]);

        rb
= Set[1 - vec[i]].find(v[i]);

        Set[1
- vec[i]].root[ra] = rb;

        Set[1
- vec[i]].dis[ra] = Set[1 - vec[i]].dis[v[i]] - Set[1 - vec[i]].dis[u[i]];

         

        for(;
S[j].tclock == i; ++j) {

            ra
= Set[0].find(S[j].u), rb = Set[0].find(S[j].v);

            if

(ra != rb) {

                ans[S[j].lab]
= -1;

                continue;

            }

            ans[S[j].lab]
+= _abs(Set[0].dis[S[j].u] - Set[0].dis[S[j].v]);

            ra
= Set[1].find(S[j].u), rb = Set[1].find(S[j].v);

            if

(ra != rb) {

                ans[S[j].lab]
= -1;

                continue;

            }

            ans[S[j].lab]
+= _abs(Set[1].dis[S[j].u] - Set[1].dis[S[j].v]);

        }

    }

     

    for(i
= 1; i <= Q; ++i)

        printf("%d\n",
ans[i]);

     

    return

0;

}

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