trap

var trap = function(height) {
        if(height <= 1) {
            return 0
        }
        else {let max = Math.max.apply(null, height);
        let indexsmax = [];
        let srez = [];
        let startval = 0;
        let centerval = 0;
        let endval = 0;
        let x = 0;
        let y = 0;

        for (i in height){
            
            if (height[i] == max){
                indexsmax.push(Number(i));
            };
        };
        indexsmax.unshift(0);
        indexsmax.push(height.length);
        let len = indexsmax.length;

        for (let i=0; i<len; i++){
            srez.push(height.slice(indexsmax[i], indexsmax[i+1]));
            if ( i != len-1){
                srez[i].push(max);
            }
        };
        srez.at(-1);
        
        let xyu =srez.at(-1);
        if (xyu.length <=2 ) {
            srez.pop();
        };

        srez.at(-1).pop();

        if (srez.at(-1).length == 1){
            srez.splice(srez.length - 1);
        }
        
        if(srez[0].length == 1){
            srez.shift();
        }
        let end = new Array();
        let start = srez.shift();
        if (srez.length !== 0){
            end = srez.pop();
        };
        
        if (start.at(-1) != max){
            start = start.reverse();
        }

        for (let i = 0; i< start.length; i ++){
            if ( start[i] >= x){
                x = start[i];
            }else {
                startval = x - start[i] + startval;
            }
        };

        end = end.reverse();

        for (let i = 0; i< end.length; i ++){
            if ( end[i] >= y){
                y = end[i];
            }else {
                endval = y - end[i] + endval;
            };
        };
        for (let i = 0; i < srez.length; i++) {
                    let node = srez[i];
                    for( let t =0; t < node.length; t++){  
                        centerval = max - node[t] + centerval
                    }
                };
        let ans = startval+centerval+endval;
        return ans