namespace fastio{
    struct{char buf[1<<20],*l=buf,*r=l;
    operator char(){return l==r&&(r=(l=buf)+fread(buf,1,1<<20,stdin),l==r)?0:*l++;}
    template<typename T>operator T(){
        T x=0;char f=0,c=*this;
        while(c<'0'||c>'9'){if(c=='-')f=1;c=*this;}
        while(c>='0'&&c<='9')x=x*10+(c^48),c=*this;
        return f?-x:x;
    }}in;signed stk[39],tp;
    template<typename T>void out(T x,char c=0){
        if(x<0)putchar('-'),x=-x;
        do stk[tp++]=x%10;while(x/=10);
        while(tp)putchar(stk[--tp]^48);
        if(c)putchar(c);
    }
}using fastio::in,fastio::out;

int main(){
    int n = in;
    for(int k=1;k<=n;k++)
        out(100000000,' ');
    return 0;
}

这是我的快读，把 signed 改成 long long 在 qoj 快了 35ms。

不理解，因为 putchar 参数是 int，我传得也是 int，long long 会发生转换，但是相反 int 发生了转换。

while(tp)putchar(stk[--tp]^48);

        mov     DWORD PTR fastio::tp[rip], eax
        cdqe
        mov     edi, DWORD PTR fastio::stk[0+rax*4]
        xor     edi, 48

这里出现了 cdqe，神秘。

下面是汇编的主要差别

int 的:

.L16:
        movsx   rax, DWORD PTR fastio::tp[rip]
        mov     esi, 100000000
        lea     ecx, [rax+1]
        lea     rdi, [rax+10]
        movsx   rcx, ecx
.L14:
        movsx   rdx, esi
        mov     r8d, esi
        mov     eax, ecx
        imul    rdx, rdx, 1717986919
        sar     r8d, 31
        sar     rdx, 34
        sub     edx, r8d
        lea     r8d, [rdx+rdx*4]
        add     r8d, r8d
        sub     esi, r8d
        mov     DWORD PTR fastio::stk[-4+rcx*4], esi
        add     rcx, 1
        mov     esi, edx
        cmp     rcx, rdi
        jne     .L14
        mov     DWORD PTR fastio::tp[rip], eax
        test    eax, eax
        je      .L17
.L15:
        sub     eax, 1
        mov     rsi, QWORD PTR stdout[rip]
        mov     DWORD PTR fastio::tp[rip], eax
        cdqe
        mov     edi, DWORD PTR fastio::stk[0+rax*4]
        xor     edi, 48
        call    putc
        mov     eax, DWORD PTR fastio::tp[rip]
        test    eax, eax
        jne     .L15

long long:

.L16:
        mov     r8, QWORD PTR fastio::tp[rip]
        mov     edi, 100000000
        lea     rax, [r8+1]
        add     r8, 10
.L14:
        movsx   rsi, edi
        mov     rcx, rax
        sar     edi, 31
        mov     rax, rsi
        mul     r12
        shr     rdx, 3
        lea     rax, [rdx+rdx*4]
        mov     rdx, rsi
        imul    rsi, rsi, 1717986919
        add     rax, rax
        sub     rdx, rax
        lea     rax, [rcx+1]
        mov     QWORD PTR fastio::stk[-8+rcx*8], rdx
        sar     rsi, 34
        sub     esi, edi
        mov     edi, esi
        cmp     r8, rax
        jne     .L14
        mov     QWORD PTR fastio::tp[rip], rcx
        test    rcx, rcx
        je      .L17
.L15:
        sub     rcx, 1
        mov     rsi, QWORD PTR stdout[rip]
        mov     rdi, QWORD PTR fastio::stk[0+rcx*8]
        mov     QWORD PTR fastio::tp[rip], rcx
        xor     edi, 48
        call    putc
        mov     rcx, QWORD PTR fastio::tp[rip]
        test    rcx, rcx
        jne     .L15