快速读入模板

    int read(){
	    int x=0,f=1;
	    char c=getchar();
	    while(c<'0'||c>'9'){
		    if(c=='-') f=-1;
		    c=getchar();
	    }
	    while(c>='0'&&c<='9'){
		    x=x*10+c-'0';
		    c=getchar();
	    }
	    return x*f;
    }

知识点补充：
https://blog.csdn.net/weixin_44551646/article/details/98076863?ops_request_misc=
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