下面一段代码的时间复杂度是?<ol style="padding: 0px; outline: none; list-style-position: initial; list-style-image: initial; font-size: 13px; line-height: 1.4em; background-color: rgb(247, 247, 249); font-family: Monaco, Menlo, Consolas, "Courier New", monospace; white-space: pre-wrap; color: rgb(175, 175, 175) !important;" class=" list-paddingleft-2"><li>if ( A > B ) {
</li><li> for ( i=0; i<N; i++ )
</li><li> for ( j=N*N; j>i; j-- )
</li><li> A += B;
</li><li>}
</li><li>else {
</li><li> for ( i=0; i<N*2; i++ )
</li><li> for ( j=N*2; j>i; j-- )
</li><li> A += B;
</li><li>}
</li></ol>