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Time Limit: 6 s Memory Limit: 512 MB Total points: 100

#1256. 再刪兩個頂點

Statistics

幾年前,同一位作者曾經為一場中學生比賽出過以下問題:喺一個最小度數至少係 $2$ 嘅連通無向圖入面,刪走兩個相鄰頂點,同時令個圖保持連通。不過,呢條題目對 2020 年嘅大學生比賽嚟講太簡單,所以就有咗今次呢條題目。

畀定一個至少有 $3$ 個頂點、冇自環亦冇重邊嘅連通無向圖。對每條邊,判斷刪走佢兩個端點之後,個圖係咪仍然連通。

留意,呢條題目嘅圖可以有度數係 $1$ 嘅頂點,但唔會有度數係 $0$ 嘅頂點(因為個圖連通,而且至少有 $3$ 個頂點)。

輸入

輸入第一行包含兩個整數 $n$ 同 $m$($3 \le n \le 3\cdot 10^5$;$n-1 \le m \le 3\cdot 10^5$),分別係頂點數同邊數。接落嚟 $m$ 行嘅第 $i$ 行包含兩個以空格分隔嘅整數 $x$ 同 $y$,即第 $i$ 條邊嘅端點($1 \le x,y \le n$;$x\ne y$)。保證個圖連通,而且冇重邊。

輸出

輸出一個長度為 $m$ 嘅二進制字串。如果刪走第 $i$ 條邊嘅兩個端點會令個圖唔連通,答案嘅第 $i$ 個字元就應該係 0(唔包括引號),否則就係 1。

樣例

輸入 1

4 4
1 2
2 3
3 1
4 1

輸出 1

0101

說明

請留意,刪走嘅唔單止係條邊本身,仲包括佢兩個端點。所以,呢個任務同搵橋唔一樣。

例如,喺樣例入面,邊 $1$–$2$ 唔係橋,但刪走頂點 $1$ 同 $2$ 會令個圖唔連通:結果個圖只剩低兩個孤立頂點 $3$ 同 $4$。

另一方面,邊 $1$–$4$ 係橋,但刪走頂點 $1$ 同 $4$ 之後,個圖仍然連通:結果個圖由頂點 $2$ 同 $3$ 組成,兩者由邊 $2$–$3$ 連住。

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