結果

問題 No.274 The Wall
ユーザー vwxyz
提出日時 2023-05-17 10:05:02
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 357 ms / 2,000 ms
コード長 3,186 bytes
コンパイル時間 306 ms
コンパイル使用メモリ 82,092 KB
実行使用メモリ 78,592 KB
最終ジャッジ日時 2024-12-15 05:29:22
合計ジャッジ時間 4,940 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge1
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ファイルパターン 結果
sample AC * 4
other AC * 22
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ソースコード

diff #
プレゼンテーションモードにする

import sys
readline=sys.stdin.readline
def SCC(N,edges):
    start = [0] * (N + 1)
    elist = [0] * len(edges)
    for e in edges:
        start[e[0] + 1] += 1
    for i in range(1, N + 1):
        start[i] += start[i - 1]
    counter = start[:]
    for e in edges:
        elist[counter[e[0]]] = e[1]
        counter[e[0]] += 1
    N = N
    now_ord = group_num = 0
    visited = []
    low = [0] * N
    order = [-1] * N
    ids = [0] * N
    parent = [-1] * N
    stack = []
    for i in range(N):
        if order[i] == -1:
            stack.append(i)
            stack.append(i)
            while stack:
                v = stack.pop()
                if order[v] == -1:
                    low[v] = order[v] = now_ord
                    now_ord += 1
                    visited.append(v)
                    for i in range(start[v], start[v + 1]):
                        to = elist[i]
                        if order[to] == -1:
                            stack.append(to)
                            stack.append(to)
                            parent[to] = v
                        else:
                            low[v] = min(low[v], order[to])
                else:
                    if low[v] == order[v]:
                        while True:
                            u = visited.pop()
                            order[u] = N
                            ids[u] = group_num
                            if u == v:
                                break
                        group_num += 1
                    if parent[v] != -1:
                        low[parent[v]] = min(low[parent[v]], low[v])
    for i, x in enumerate(ids):
        ids[i] = group_num - 1 - x
    groups = [[] for _ in range(group_num)]
    for i, x in enumerate(ids):
        groups[x].append(i)
    return groups
class TwoSAT:
    def __init__(self,N):
        self.N=N
        self.edges=[]
    def Add_Clause(self,i,f,j,g):
        assert 0<=i<self.N
        assert 0<=j<self.N
        self.edges.append((2*i+(0 if f else 1),2*j+(1 if g else 0)))
        self.edges.append((2*j+(0 if g else 1),2*i+(1 if f else 0)))
    def Satisfiable(self):
        scc=SCC(2*self.N,self.edges)
        idx=[None]*2*self.N
        for i,lst in enumerate(scc):
            for x in lst:
                idx[x]=i
        retu=[None]*self.N
        for i in range(self.N):
            if idx[2*i]==idx[2*i+1]:
                return None
            retu[i]=idx[2*i]<idx[2*i+1]
        return retu
N,M=map(int,readline().split())
L,R=[],[]
for n in range(N):
    l,r=map(int,readline().split())
    r+=1
    L.append(l)
    R.append(r)
if sum(r-l for l,r in zip(L,R))>M:
    print("NO")
    exit()
TSAT=TwoSAT(N)
for i in range(N):
    for j in range(i+1,N):
        for bi in (0,1):
            if bi==0:
                li,ri=L[i],R[i]
            else:
                li,ri=M-R[i],M-L[i]
            for bj in (0,1):
                if bj==0:
                    lj,rj=L[j],R[j]
                else:
                    lj,rj=M-R[j],M-L[j]
                if max(li,lj)<min(ri,rj):
                    TSAT.Add_Clause(i,bi,j,bj)
if TSAT.Satisfiable():
    ans="YES"
else:
    ans="NO"
print(ans)
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