��一起，对于上面数字1到7就成了110100101100010011010... <br />
对于这样一个无限长的字符串，问前N个字符中有多少个1 <br />
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</font></p></div></div></div></div><div class="row"><div class="column"><h4 class="ui top attached block header">输入格式</h4><div class="ui bottom attached segment font-content"><div style="position: relative; overflow: hidden;"><div class=content><p><font face="Times New Roman" size="3">一个数字N，N &lt; = 10^15</font></p></div></di