代码

#include<cstdio>
using namespace std;
char buf[1000000],*p1=buf,*p2=buf;
inline int getc(){
	return p1==p2&&(p2=(p1=buf)+fread(buf,1,1000000,stdin),p1==p2)?EOF:*p1++;
}
inline int getint(){
    int ans=0;
    char c=getc();
    while(c<'0'||c>'9')c=getc();//' '<'0'
    while(c>='0'&&c<='9'){
    	ans*=10;
        ans+=c-'0';
        c=getc();
    }
    return ans;
}
int main(){
    int n=getint();
    register char c;
    register int lst=0,ans=0,x;
    for(register int i=n;i;--i){
	    x=0;
	    c=getc();
	    while(c<'0'||c>'9')c=getc();//' '<'0'
	    while(c>='0'&&c<='9'){
	    	x*=10;
	        x+=c-'0';
	        c=getc();
	    }
        if(x-lst>0)ans+=(x-lst);
        lst=x;
    }
    printf("%d",ans);
    return 0;
}
//丧心病狂

评测结果