Submission #6237991

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Source Code Expand

import sys
input = sys.stdin.readline

N,L = map(int,input().split())
# (右向き・左向き)でセット
left = []
right = []
last = 'R'

def F(left,right):
    l_cnt,l_sum = len(left), sum(left)
    r_cnt,r_sum = len(right), sum(right)
    # 集合場所
    if r_cnt == 0:
        P = 0, 1
    elif l_cnt == 0:
        P = L, L+1
    else:
        # 少人数側に寄せる
        if l_cnt < r_cnt:
            P = left[0]-1, left[0]
        else:
            P = right[-1], right[-1]+1
    # 右向きの移動距離
    x = (P[0] + P[0] - r_cnt + 1) * r_cnt // 2 - r_sum
    # 左向きの移動距離
    x += l_sum - (P[1] + P[1] + l_cnt - 1) * l_cnt // 2
    return x

answer = 0
for _ in range(N):
    x,d = input().split()
    x = int(x)
    if d == 'R':
        if last == 'R':
            right.append(x)
        else:
            # 一区切りになった
            last = 'R'
            answer += F(left,right)
            left = []
            right = [x]
    else:
        last = 'L'
        left.append(x)
answer += F(left,right)

print(answer)

Submission Info

Judge Result