整数中出现1的个数
class Solution {
public:
int NumberOf1Between1AndN_Solution(int n)
{
int dev = 10; //除数
int multi = 1;
int res = 0;
int low;
int cur = n%dev; //最初为个位数
int high = n / dev; //high从十位开始
int flag = false;
while(n / multi) //当高位数存在时
{
if(cur > 1)
res = res+ (high+1) *multi;
if(cur == 1)
{
if(flag)
res =res + high * multi + low+1;
else
res =1;
}
if(cur == 0)
{
res = res + high * multi;
}
flag = true;
dev *= 10;
multi *= 10;
high = n / dev;
cur = (n - high *dev) / multi;
low = n - high*dev - cur *multi;
}
return res;
}};
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