leetcode-rust/src/a0400_nth_digit.rs at master · liguangsheng/leetcode-rust · GitHub

Name: leetcode-rust/src/a0400_nth_digit.rs at master · liguangsheng/leetcode-rust · GitHub
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/*
 * [0400] nth-digit
 */

pubstructSolution{}

// solution impl starts here

implSolution{
pubfnfind_nth_digit(n:i32) -> i32{
letmut n:u32 = n asu32;
letmut x:u32 = 0;
letmut right:u32 = 0;

// 确定数字区间
while n > right {
 x += 1;
 n -= right;
 right = 10u32.pow(x - 1)* x *9;
}

// 取出数字
((10u32.pow(x - 1) + (n - 1) / x) / 10u32.pow(if n % x > 0{ x - n % x }else{0}) % 10)
asi32
}
}

// solution impl ends here

// solution tests starts here

#[cfg(test)]
mod tests {
usesuper::*;

#[test]
fntest_case0(){
assert_eq!(Solution::find_nth_digit(3),3);
assert_eq!(Solution::find_nth_digit(10),1);
assert_eq!(Solution::find_nth_digit(11),0);
assert_eq!(Solution::find_nth_digit(12),1);
assert_eq!(Solution::find_nth_digit(1000),3);
}
}

// solution tests ends here