链接：[https://ac.nowcoder.com/acm/contest/81597/H]
来源：牛客网
题目描述
Red stands at the coordinate \((0,0)\) of the Cartesian coordinate system. She has a string of instructions: up, down, left, right (where 'right' increases the x-coordinate by \(1\), and 'up' increases the y-coordinate by \(1\)).Now Red wants to select a continuous substring of instructions and execute them. Red hopes that the final execution of the instructions can pass through the coordinate \((x,y)\). She wants to know how many selection options there are.
输入描述:
The first line contains three integers \(n\), \(x\), and \(y\) ( \(1≤n≤2×10^5\),\(−10^5≤
标签：前缀,int,题解,多校,牛客,second,哈希,区间,first From： https://www.cnblogs.com/cxjy0322/p/18310594