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/**
* @license Apache-2.0
*
* Copyright (c) 2026 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*    http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
 
'use strict';
 
// MODULES //
 
var sfirstIndexEqual = require( '@stdlib/blas/ext/base/sfirst-index-equal' ).ndarray;
 
 
// MAIN //
 
/**
* Returns the index of the last element in a single-precision floating-point strided array equal to a corresponding element in another single-precision floating-point strided array using alternative indexing semantics.
*
* ## Notes
*
* -   If the function is unable to find an element in `x` which is equal to a corresponding element in `y`, the function returns `-1`.
*
* @param {PositiveInteger} N - number of indexed elements
* @param {Float32Array} x - first input array
* @param {integer} strideX - stride length for `x`
* @param {NonNegativeInteger} offsetX - starting index for `x`
* @param {Float32Array} y - second input array
* @param {integer} strideY - stride length for `y`
* @param {NonNegativeInteger} offsetY - starting index for `y`
* @returns {integer} index
*
* @example
* var Float32Array = require( '@stdlib/array/float32' );
*
* var x = new Float32Array( [ 1.0, 2.0, 3.0, 4.0 ] );
* var y = new Float32Array( [ 0.0, 0.0, 3.0, 0.0 ] );
*
* var idx = slastIndexEqual( x.length, x, 1, 0, y, 1, 0 );
* // returns 2
*/
function slastIndexEqual( N, x, strideX, offsetX, y, strideY, offsetY ) {
	var idx;
	var ox;
	var oy;
	var sx;
	var sy;

	if ( N <= 0 ) {
		return -1;
	}
	// Reverse the iteration order by flipping the strides and adjusting the offsets:
	ox = offsetX + ( ( N - 1 ) * strideX );
	oy = offsetY + ( ( N - 1 ) * strideY );
	sx = -strideX;
	sy = -strideY;

	// Find the index of the first matching element in the reversed "views":
	idx = sfirstIndexEqual( N, x, sx, ox, y, sy, oy );
	if ( idx < 0 ) {
		return idx;
	}
	// Convert the index from the reversed "views" to an index in the original "views":
	return N - 1 - idx;
}
 
 
// EXPORTS //
 
module.exports = slastIndexEqual;