CF1476F.Lanterns

普及/提高-

通过率:0%

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题目描述

There are nn lanterns in a row. The lantern ii is placed in position ii and has power equal to pip_i .

Each lantern can be directed to illuminate either some lanterns to the left or some lanterns to the right. If the ii -th lantern is turned to the left, it illuminates all such lanterns jj that j[ipi,i1]j \in [i - p_i, i - 1] . Similarly, if it is turned to the right, it illuminates all such lanterns jj that j[i+1,i+pi]j \in [i + 1, i + p_i] .

Your goal is to choose a direction for each lantern so each lantern is illuminated by at least one other lantern, or report that it is impossible.

输入格式

The first line contains one integer tt ( 1t100001 \le t \le 10000 ) — the number of test cases.

Each test case consists of two lines. The first line contains one integer nn ( 2n31052 \le n \le 3 \cdot 10^5 ) — the number of lanterns.

The second line contains nn integers p1,p2,,pnp_1, p_2, \dots, p_n ( 0pin0 \le p_i \le n ) — the power of the ii -th lantern.

The sum of nn over all test cases does not exceed 31053 \cdot 10^5 .

输出格式

For each test case, print the answer as follows:

If it is possible to direct all lanterns so that each lantern is illuminated, print YES in the first line and a string of nn characters L and/or R (the ii -th character is L if the ii -th lantern is turned to the left, otherwise this character is R) in the second line. If there are multiple answers, you may print any of them.

If there is no answer, simply print NO for that test case.

输入输出样例

  • 输入#1

    4
    8
    0 0 3 1 1 1 1 2
    2
    1 1
    2
    2 2
    2
    0 1

    输出#1

    YES
    RRLLLLRL
    YES
    RL
    YES
    RL
    NO
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