LITE - Light Switching

# 题目描述 灯是由高科技——外星人鼠标操控的。你只要左击两个灯所连的鼠标， 这两个灯，以及之间的灯都会由暗变亮，或由亮变暗。右击两个灯所连的鼠 标，你就可以知道这两个灯，以及之间的灯有多少灯是亮的。起初所有灯都是暗的，你的任务是在LZ之前算出灯的亮灭。 # 输入输出格式 第 $1$ 行：用空格隔开的两个整数 $N$ 和 $M$，$N$ 是灯数。 第 $2 \dots M+1$ 行：每行表示一个操作, 有三个用空格分开的整数：指令号，$S_i$ 和 $E_i$。 第 $1$ 种指令（用 `0` 表示）包含两个数字 $S_i$ 和 $E_i$（$1 \leq S_i \leq E_i \leq N$），它们表示起始开关和终止开关。 第 $2$ 种指令（用 `1` 表示）同样包含两个数字 $S_i$ 和 $E_i$（$1 \leq S_i \leq E_i \leq N$），不过这种指令是询问从 $S_i$ 到 $E_i$ 之间的灯有多少是亮着的。 ## 输出格式 每当遇到第二种指令时，输出一行，包含一个整数：此时在查询的区间中打开的灯的数目。

Farmer John tries to keep the cows sharp by letting them play with intellectual toys. One of the larger toys is the lights in the barn. Each of the N (2 <= N <= 100,000) cow stalls conveniently numbered 1..N has a colorful light above it. At the beginning of the evening, all the lights are off. The cows control the lights with a set of N pushbutton switches that toggle the lights; pushing switch i changes the state of light i from off to on or from on to off. The cows read and execute a list of M (1 <= M <= 100,000) operations expressed as one of two integers (0 <= operation <= 1). The first kind of operation (denoted by a 0 command) includes two subsequent integers S\_i and E\_i (1 <= S\_i <= E\_i <= N) that indicate a starting switch and ending switch. They execute the operation by pushing each pushbutton from S\_i through E\_i inclusive exactly once. The second kind of operation (denoted by a 1 command) asks the cows to count how many lights are on in the range given by two integers S\_i and E\_i (1 <= S\_i <= E\_i <= N) which specify the inclusive range in which the cows should count the number of lights that are on. Help FJ ensure the cows are getting the correct answer by processing the list and producing the proper counts.

Line 1: Two space-separated integers: N and M Lines 2..M+1: Each line represents an operation with three space-separated integers: operation, S\_i, and E\_i

Lines 1..number of queries: For each output query, print the count as an integer by itself on a single line.

4 5
0 1 2
0 2 4
1 2 3
0 2 4
1 1 4

1
2