Binary search

<div class="v"><header><b>BINARY SEARCH</b><span id="state"></span></header><main><div class="nums" id="nums"></div><div class="target">target <b>7</b></div></main><footer>halve the range</footer></div>

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let lo=0,hi=8;const nums=[1,2,3,4,5,6,7,8,9],box=document.getElementById("nums");function step(){if(lo>hi){lo=0;hi=8}const mid=Math.floor((lo+hi)/2);box.replaceChildren(...nums.map((n,i)=>{let x=document.createElement("i");x.textContent=n;x.className=(i<lo||i>hi?"muted ":"")+(i===mid?"active":"");return x}));document.getElementById("state").textContent="middle="+nums[mid];if(nums[mid]<7)lo=mid+1;else if(nums[mid]>7)hi=mid-1;else{lo=10}}step();setInterval(step,900)